IMAP4 and POP3 not working w/Exchange5.5

How can we configure Exchange server 5.5 to communicate
with a users’ IPAQ handheld or mobile phone?

We had to close the third party routing on Exchange 5.5
to stop spammers from using our Exchange server to send
spam email.

When we did this is seem to close parts of IMAP4 and POP3
send and receive from Exchange server to mobile devices such as IPAQ and Cell phones.

Any help would be greatly appreciated.

Thanks.