How to tell ASM that a POST is valid?

Hi out there We have a webserver which is accessed through a F5 with LTM, APM & ASM - there has been implemented a function now where the customer can upload a file from there PC to the site This also works more or less fine but the ASM module is blocking the session because the POST is recognized as a buffer overflow attack. When I look at the session the ASM module says: File Type asp Detected Request Length 1577565 Expected Request Length 100000 and the post: File Type asp Detected POST Data Length 1576349 Expected POST Data Length 100000

I can wonder why the request and the POSt isnt equal but - ?? - anyway - I can of course just increase the length's permitted there from 100.000 to 2.000.000 (probably) but since we here are talking about jpg files they might become even bigger. What would be the correct way to handle this problem in?

best regards /ti