Help Activesync Security Policy Problem

[Morat]

Hello,
I've got my Desire syncing quite happily with Exchange. I noticed that it hadn't imposed security policies on the phone. I shrugged and thought that this must be a limitation with Android. However, when I had my Touch HD replaced under warranty that didn't have the security policies imposed either.
Oh Ho.

So, I created a new policy in Exchange and applied it to just myself. The requirement is for a simple PIN every hour. This is working fine on my Touch HD but the Desire wants a PIN every...freaking....time...it....sleeps....
As soon as the screen goes black, it wants a PIN on wake-up. This is getting on my nerves.

Is the Desire capable of asking for a PIN after an hour of non-use? Or is it impossible and the phone is getting as close as it can to the correct policy?

TIA
Morat