imap mail - sent items not replicated

i have my email account set up on my touch, it's an IMAP account.

when i send an email, it appears to place the email in a sent items folder that only exists on the device, and doesn't place it in my actual email account sent items.

when i check my email account on webmail, the email is not in sent items.

the same is the case for deleted items.

what settings do i need to change so that these are properly replicated?

my mailbox behaviours on the deviceare:

drafts mailbox : Drafts
sent mailbox : Sent Messages
Deleted mailbox : Deleted Messages
IMAP Path prefix : /