Sending mail with attachment from Photos App get stuck in Outbox iPhone

Hey,
As it is described in the title, the photos I have previously selected in Photos App ( by clicking send > by mail ) get stucked in my Outbox.
In opposition to some other discussions, I can edit/delete that stucked mail, and even send it if I manually click again on Send from the outbox !
Other funny conclusion : If I copy&paste the photo and compose a new message from the Mail App, the same mail isnt stuck.
I tried to delete/reconfigure my Exchange Account, it doesnt change anything.
Google Mail account configured with Exchange Account.
Synchronising Mail&Calendar
Push activated
(It definitely worked properly before)
Device: Iphone 4
Carrier: Orange France
Country / Language: FR
OS / Browser / build number (if applicable): iOS 4.1 8B117
Iphone 4 iOS 4 iOS 4.1 8B117