[WD20/WM20] Call of a WebService procedure "hangs" the app

Hi,
I'm going to develop 2 apps, 1 for PC and 1 for Windows Mobile.
In both the apps I use a lot of WebService procedures, but...

If my WebService is down the app hangs for about 1 minute.
No way to escape from this locked situation (even with Threads).

Ps. Parallel tasks are not a good way because they are not available for Windows Mobile

Thanks,
Dann