Synch to MSN

Hi everyone.
I have a premium MSN account and have set up to view my e-mails on my Blackberry Curve. The only issue is that when I delete and e-mail on my Blackberry, the email does not delete from my Hotmail account. Similiary, when I delete in my hotmail account it doesn't delete on my Blackberry. It's driving me mad and getting a bit confusing. Can anyone help?

BTW If anyone replies then please bear in mind I've only had a Blackberry for about 3 days so am not an expert at all.

Cheers
Mark