Request/session timeout when exporting very large files

[Simon Sew]

Hi,
I'm having this request/session timeout problem.

My page have a link to generate and export pdf file. The problem is sometimes 
the generated file is very huge (100MB++) and it takes quite some time to 
export it (30 to 90 minutes). How do I prevent it from timeout when it is 
exporting at that time?

I tried session.setMaxInactiveInterval() but it's not working.

Thx.