How to use Taxonomy Facets together with Apache Solr Multisite Search ?
A little patch that solve the issue

Index: apachesolr_multisitesearch.module
===================================================================
--- apachesolr_multisitesearch.module   (révision 32470)
+++ apachesolr_multisitesearch.module   (copie de travail)
@@ -331,6 +331,10 @@
             return apachesolr_date_facet_block($response, $query, 'apachesolr_multisitesearch', $delta, $delta, t('Filter by post date'));
           case 'hash':
             return apachesolr_facet_block($response, $query, 'apachesolr_multisitesearch', $delta, $delta, t('Filter by site'), 'theme_apachesolr_breadcrumb_hash');
+            
+           //syg on ajoute un retour pours toutes les autres facets
+          default:
+            return apachesolr_facet_block($response, $query, 'apachesolr_multisitesearch', $delta, $delta, t('Filter by %field', array('%field'=&gt; $delta)));
         }
       }
       break;