kmail attachment size

Hello all Today I wanted to send a somewhat large PDF and a "sorry" window poped up saying: "Your administrator has disallowed attaching files bigger than 50MB". Being teh administrator, I can't remember ever settting this limit, but more important: I have no idea where this setting is controled. I don't know of any "administrator" settings in TDE, I can't find anything in kmail's settings. Is kmail looking anywhere else for this limitation? Regards, Thierry