finally, it works

fulcrm_shoppingcart.module

@@ -289,8 +289,8 @@ function fulcrm_shoppingcart_person_add_guest_form_submit( $form, &$form_state )
         if ( $api_data[ 'success' ] ) {
             module_invoke_all( 'fulcrm_shoppingcart_person_add', $api_data[ 'data' ], array_key_exists( 'destination', $_GET ) ? $_GET[ 'destination' ] : variable_get( 'fulcrm_shoppingcart_proceed_url', url('<front>') ) );
 
-            $form_state[ 'fulcrm_collection' ][ 'person' ] = $person_data;
+            $form_state[ 'fulcrm_shoppingcart' ][ 'person' ] = $person_data;
-            $form_state[ 'fulcrm_collection' ][ 'shoppingcart' ] = $api_data[ 'data' ];
+            $form_state[ 'fulcrm_shoppingcart' ][ 'shoppingcart' ] = $api_data[ 'data' ];
         } else {
             drupal_set_message( t('There was a problem adding your item to the shopping cart.'), 'error' );
         }
@@ -364,7 +364,7 @@ function _fulcrm_shoppingcart_buy_eventbookingtype_create_shoppingitem( &$form_s
         $api_data = fulcrm_apiv2_POST( 'shoppingitem/', $item, $query = array( 'expand' => 'd' ) );
         fulcrm_shoppingcart_invalidate_cache();
         if ( $api_data[ 'success' ] ) {
-            $hook_results = module_invoke_all( 'fulcrm_shoppingcart_post_add_to_cart', $cart, $person_data[ 'data' ], $api_data[ 'data' ] );
+            $hook_results = module_invoke_all( 'fulcrm_shoppingcart_post_add_to_cart', $cart, $api_data[ 'data' ] );
             foreach ( $hook_results as $hook_result )
                 return $hook_result;
 
@@ -387,13 +387,20 @@ function fulcrm_shoppingcart_buy_eventbookingtype_form_submit( $form, &$form_sta
     if ( array_key_exists( 'uuid', $form_state[ 'fulcrm_shoppingcart' ][ 'person' ] ) )
         $person_uuid = $form_state[ 'fulcrm_shoppingcart' ][ 'person' ][ 'uuid' ];
 
-    if ( array_key_exists( 'shoppingcart', $form_state[ 'fulcrm_shoppingcart' ] ) )
+    $cart = fulcrm_shoppingcart_get_session_cart();
-        $cart = $form_state[ 'fulcrm_shoppingcart' ][ 'shoppingcart' ];
-    else
-        $cart = fulcrm_shoppingcart_get_session_cart();
 
     if ( $cart ) {
+        if ( !$person_uuid ) {
+            if ( array_key_exists( 'd', $cart ) &&
+                 array_key_exists( 'fulcrm', $cart[ 'd' ] ) &&
+                 array_key_exists( 'transaction', $cart[ 'd' ][ 'fulcrm' ] ) &&
+                 array_key_exists( 'person', $cart[ 'd' ][ 'fulcrm' ][ 'transaction' ] )
+                 ) {
+                $person_uuid = $cart[ 'd' ][ 'fulcrm' ][ 'transaction' ][ 'person' ];
+            }
+        }
         if ( $person_uuid ) {
+            $patch = FALSE;
             if ( !array_key_exists( 'fulcrm', $cart[ 'd' ] ) ||
                  !array_key_exists( 'person', $cart[ 'd' ][ 'fulcrm' ] ) ||
                  !array_key_exists( $person_uuid, $cart[ 'd' ][ 'fulcrm' ][ 'person' ] ) ) {
@@ -409,6 +416,11 @@ function fulcrm_shoppingcart_buy_eventbookingtype_form_submit( $form, &$form_sta
             if ( $patch ) {
                 $api_data = fulcrm_apiv2_PATCH( $cart[ 'url' ], array( 'd' => $cart[ 'd' ] ),
                                                 $query = array( 'expand' => 'd' ) );
+                if ( $api_data[ 'success' ] ) {
+                    $cart = $api_data[ 'data' ];
+                } else {
+                    drupal_set_message( t('There was a problem adding your item to the shopping cart.'), 'error' );
+                }
                 fulcrm_shoppingcart_invalidate_cache();
             }
         }
@@ -439,15 +451,14 @@ function fulcrm_shoppingcart_buy_eventbookingtype_form_submit( $form, &$form_sta
     } else {
         drupal_set_message( t('There was a problem adding your item to the shopping cart.'), 'error' );
     }
-
-    $form_state[ 'fulcrm_shoppingcart' ][ 'shoppingcart' ] = $cart;
 }
 
 function fulcrm_shoppingcart_buy_eventbookingtype_person_add_guest_form_submit( $form, &$form_state ) {
     fulcrm_shoppingcart_person_add_guest_form_submit( $form, $form_state );
     if ( array_key_exists( 'person', $form_state[ 'fulcrm_shoppingcart' ] ) ) {
         fulcrm_shoppingcart_buy_eventbookingtype_form_submit( $form, $form_state );        
-        // XXXXXX
+    } else {
+        drupal_set_message( t('There was a problem adding your item to the shopping cart.'), 'error' );
     }
 }
 
@@ -609,10 +620,7 @@ function fulcrm_shoppingcart_buy_generic_product_form_submit( $form, &$form_stat
          array_key_exists( 'uuid', $form_state[ 'fulcrm_shoppingcart' ][ 'person' ] ) )
         $person_uuid = $form_state[ 'fulcrm_shoppingcart' ][ 'person' ][ 'uuid' ];
 
-    if ( array_key_exists( 'shoppingcart', $form_state[ 'fulcrm_shoppingcart' ] ) )
+    $cart = fulcrm_shoppingcart_get_session_cart();
-        $cart = $form_state[ 'fulcrm_shoppingcart' ][ 'shoppingcart' ];
-    else
-        $cart = fulcrm_shoppingcart_get_session_cart();
 
     if ( is_array( $cart ) ) {
         if ( $person_uuid ) {
@@ -655,8 +663,6 @@ function fulcrm_shoppingcart_buy_generic_product_form_submit( $form, &$form_stat
     } else {
         drupal_set_message( t('There was a problem adding your item to the shopping cart.'), 'error' );
     }
-
-    $form_state[ 'fulcrm_shoppingcart' ][ 'shoppingcart' ] = $cart;
 }
 
 function fulcrm_shoppingcart_buy_generic_product_form( $form, &$form_state, $person, $product ) {