Can any Android users help with this?

I'm using Exchange active sync with my hotmail account and it's working pretty well, I can use the calendar and contacts and they all sync. The only problem that I'm having is that when I read a message or mark it as read it appears as unread if I refresh the page or when it next syncs. This is annoying as every time it syncs I think I have new mail only to find it's one that I've already read.

Any ideas?

Thanks

It's a HTC Desire S