[imp] Trouble with compose window

[lst_hoe at kwsoft.de]

Hello

we have trouble with composing messages that contain attachments. If the 
attachment get bigger then certain size the compose window state return a 
browser error message about no content. The message is send fine with the 
attachment but users try to send the message again and again because the lack 
of feedback :-(
>From what i can see the error result from some timeout. If the server uses more 
then 6-7 sec. to queue the mail this problem arises. Is this browser related or 
can i alter some timeout in the PHP-code?
Is there maybe a possibility to send some "keepalive" to the browser until the 
mail queuing has finished?

Thanxs for any help

Andreas