Question [Q] e-mail sync problems with Kerio mailserver

Hi there,
I do have a sync problem with my HTC HD2 with all versions of Android.
If i sync my account, contacts works fine, agenda works fine, but e-mails in sub-folders does not always sync completely.
I did read somewhere that it could be because of certain characters in the subject of the e-mails, but also in sub-folders that do not contain these e-mail the sync is not 100% complete.
If anyone does have an idea?