diff --git a/OpenChange/MAPIStoreMailVolatileMessage.m b/OpenChange/MAPIStoreMailVolatileMessage.m
index 77d6294ab..7ef2c2c96 100644
--- a/OpenChange/MAPIStoreMailVolatileMessage.m
+++ b/OpenChange/MAPIStoreMailVolatileMessage.m
@@ -28,6 +28,7 @@
 #import <Foundation/NSArray.h>
 #import <Foundation/NSData.h>
 #import <Foundation/NSDictionary.h>
+#import <Foundation/NSScanner.h>
 #import <Foundation/NSString.h>
 #import <Foundation/NSValue.h>
 #import <NGExtensions/NGBase64Coding.h>
@@ -541,6 +542,7 @@ FillMessageHeadersFromSharingProperties (NGMutableHashMap *headers, NSDictionary
      about the properties */
 
   id value;
+  NSNumber *sharingFlavourNum = nil;
 
   value = [mailProperties objectForKey: MAPIPropertyKey (PidLidSharingCapabilities)];
   if (value)
@@ -549,8 +551,32 @@ FillMessageHeadersFromSharingProperties (NGMutableHashMap *headers, NSDictionary
 
   value = [mailProperties objectForKey: MAPIPropertyKey (PidLidSharingFlavor)];
   if (value)
-    [headers setObject: value
-                forKey: @"X-MS-Sharing-Flavor"];
+    sharingFlavourNum = (NSNumber *)value;
+  else
+    {
+      value = [mailProperties objectForKey: MAPIPropertyKey (PidNameXSharingFlavor)];
+      if (value)
+        {
+          /* Transform the hex string to unsigned int */
+          NSScanner *scanner;
+          unsigned int sharingFlavour;
+          scanner = [NSScanner scannerWithString:value];
+          if ([scanner scanHexInt:&sharingFlavour])
+            sharingFlavourNum =[NSNumber numberWithUnsignedInt: sharingFlavour];
+        }
+    }
+  if (sharingFlavourNum)
+    {
+      if ([sharingFlavourNum unsignedIntegerValue] == 0x5100)
+        {
+          /* 0x5100 sharing flavour is not in standard but it seems to
+             be a denial of request + invitation message so we store
+             deny sharing flavour */
+          sharingFlavourNum = [NSNumber numberWithUnsignedInt: 0x25100];
+        }
+      [headers setObject: sharingFlavourNum
+                  forKey: @"X-MS-Sharing-Flavor"];
+    }
 
   value = [mailProperties objectForKey: MAPIPropertyKey (PidLidSharingInitiatorEntryId)];
   if (value)
diff --git a/OpenChange/MAPIStoreSharingMessage.m b/OpenChange/MAPIStoreSharingMessage.m
index 339ca0750..67a133bd8 100644
--- a/OpenChange/MAPIStoreSharingMessage.m
+++ b/OpenChange/MAPIStoreSharingMessage.m
@@ -134,7 +134,8 @@
   value = [properties objectForKey: @"x-ms-sharing-capabilities"];
   if (value)
     {
-      *data = [[value stringValue] asUnicodeInMemCtx: memCtx];
+      *data = [[NSString stringWithFormat:@"%X", [value intValue]]
+                 asUnicodeInMemCtx: memCtx];
       rc = MAPISTORE_SUCCESS;
     }
 
@@ -177,7 +178,7 @@
           if ([value intValue] == 0x40290)  /* Special folder */
             {
               value = [properties objectForKey: @"x-ms-sharing-responsetime"];
-              auxValue = [properties objectForKey: @"x-ms-sharing-remotename"];
+              auxValue = [properties objectForKey: @"x-ms-sharing-remoteuid"];
               if (value)  /* A sharing request */
                 {
                   if (auxValue)
@@ -187,10 +188,10 @@
                 }
               else
                 {
-                  if (auxValue)  /* It SHOULD be an invitation or response acceptance */
+                  if (auxValue)  /* It SHOULD be an invitation or response */
                     *data = MAPILongValue (memCtx, 0x20310);
-                  else
-                    *data = MAPILongValue (memCtx, 0x23310);
+                  else  /* No remote info, then denial */
+                    *data = MAPILongValue (memCtx, 0x25100);
                 }
             }
           else
@@ -213,7 +214,8 @@
   value = [properties objectForKey: @"x-ms-sharing-flavor"];
   if (value)
     {
-      *data = [[value stringValue] asUnicodeInMemCtx: memCtx];
+      *data = [[NSString stringWithFormat:@"%X", [value intValue]]
+                asUnicodeInMemCtx: memCtx];
       rc = MAPISTORE_SUCCESS;
     }