Concurrent requests with same sessionID?

[tomeg]

Is it possible to serve two concurrent requests with the same sessionID?


I'm making an ajax-chat, on the serverside it looks like this when you are polling for new messages(simplified!):

while(noNewMessages || 60secs passed since request started)
{
Thread.Sleep(1);
}
Print(newMessages);

So when a new message has arrived the javascript will get the message instantly and print it in the browser.


At the same time i want to be able to upload a chatmessage but this doesn't work because the sessionID is in use by the download-request. So when i try to send a request to Upload.aspx the browser will start loading forever because asp can't serve 2 requests with same sessionID. Sometimes i get a hole every 60sec where the sessionID is free but in most cases this doesn't happend. And even if it would happen every time 60secs is way to much!
And decreasing the timeout in Download.aspx is not a good solution, i want to be able to use the id at the same time to get no delay in eighter up- or download.


So...is there any way to do this or do i have to write my own session-manager using cookies and randomizing id-numbers myself?