Android 2.x and 3.x syncing random subfolders from exchange

I had a problem which took me quite some time to find out.
I had a 2.x android phone and a 3.x Tablet. Both of them connected fine to my exchange 2010 server. But upon syncing I saw that it would seem to sync the subfolders randomly. By that I mean that not all subfolders were showing on my device.
After some troubleshooting I deleted one of the subfolders and recreated it. After doing that the subfolder would sync to the devices without problem.
So knowing this I remembered that these problemfolders were imported from a PST and NOT created in outlook/OWA by myself. After some investigating on this it turns out that exchange gives different 'types' to subfolders when created.
So then I had to go and create a new subfolder, move the mail and delete the old one. Then renamed the subfolder to it's predecessor and it started syncing without problems.