Service crash when returning array of dictionary

I implemented an exported object possessing several standard dbus properties, one of theses properties is a Dictionnary of < string, Dictionnary of <string, object> when I query this property via GetAll it return without problem when I do a Get on this particular property it doesn't respond and the whole service seems to have crashed.

See attached test case which you can compile with :
gmcs \
  -debug \
  -out:TestService.exe \
  -target:exe\
  -r:Mono.Posix \
  `pkg-config --libs ndesk-dbus-1.0 ndesk-dbus-glib-1.0` \
  -pkg:gtk-sharp-2.0 \
  TestExport.cs \

Output:
$ dbus-send --print-reply --dest="org.ndesk.gtest" "/org/ndesk/test" "org.freedesktop.DBus.Properties.GetAll" string:"org.ndesk.gtest"
method return sender=:1.585 -> dest=:1.586 reply_serial=2
   array [
      dict entry(
         string "HandlerChannelFilter"
         variant array [
               array [
                  dict entry(
                     string "TargetHandleType"
                     variant int32 1
                  )
                  dict entry(
                     string "ContentType"
                     variant string "application/x-note"
                  )
               ]
            ]
      )
   ]

$ dbus-send --print-reply --dest="org.ndesk.gtest" "/org/ndesk/test" "org.freedesktop.DBus.Properties.Get" string:"org.ndesk.gtest" string:"HandlerChannelFilter"
Error org.freedesktop.DBus.Error.NoReply: Message did not receive a reply (timeout by message bus)

$ dbus-send --print-reply --dest="org.ndesk.gtest" "/org/ndesk/test" "org.freedesktop.DBus.Properties.GetAll" string:"org.ndesk.gtest"
Error org.freedesktop.DBus.Error.ServiceUnknown: The name org.ndesk.gtest was not provided by any .service files

Also I noticed that when FileTransferFilter is empty both method make the service crash