So your corporate exchange server pushes an Password Policy? After a couple of minutes idle time, your device is locked and you have to enter a PIN?
You can remove this by following these steps:
1) Download and start a registry editor for you windows mobile device
2) Find and change the registry key: HKLM/Security/Policies/Policies/00001023 to value 1
3) Close the registry editor and on your mobile device navigate to start, settings, lock and disable the “Prompt if device unused for” checkbox
4) Most exchange servers push this policy every once and a while, so install download and install this .CAB file on your device to make this setting permanent.
Your device will never be locked again. Credits go out to XDA developers and Zenyee.