使用AJAX更新面板时，HTML输入无法正常使用

I have some update panels on my page that do some asyncpostbacks to keep some dropdownlists correctly populated. My problem is that on my page i have an HTML input that is handling some file uploads. With the AJAX on the page with asyncpostbacks, and while i step through my code behind, the files arent being uploaded. Using a postbacktrigger (non-async) is not possible because of my layout. I have some update panels on my page that do so