UI Freeze While Using ANE on iPAD using AIR 3.7 for mobile

Hi

am building an iOS app using AIR 3.7 with flex 4.6 builder. We have created our own ANE which will download all the contents of a zip folder ( originally placed on a seperate location using http request ) on ..library/cache directory of the iPAD device.

We have no issues using the ANE but the problem occurs when downloading process is Going-ON at the back-end , the UI of the app freezes until we got "DownloadComplete", an Event Dispatched after downloading process is complete, response from the ANE.

I have also read about worker class for multi-threading but i guess it is still not supported for iOS even in AIR 3.9 beta.

Can anyone suggest a possible way, how can i make my ANE work along with the UI changes.

I have a release date near this end of the month so please guys help me out !

thanks in advance.