[naterfi]

Easyst way to do it.

just go to the Mail.yourcompany.com or companys exchange mail site and left Click the little lock, at the top right of the screen IE 7.0 or bottom right in IE 6.0

click - view certificates
click - details tab
click - copy to file
click - next
click - DER encoded radio button
click - Browse

save it to a location on your computer like desktop
then Transfer .CER file to phone

(on mogul)
Use file explorer
Click on Certificate
it will ask you to install it, say yes

soft reset phone.
then try to sync with activesync.

should work, if not check and see of the domain, username, password is right in the server source.

by the way,
activesync service should be enabled by default on the exchange server.

Good luck,
Nathan