Email seems to be a challenge on the Evo

I have two email accounts: an AOL email, and a webmail for my university. On both email accounts, there is no option to delete email from phone without deleting from server, which is a huge no-no, so I made a GMAIL account, and imported both emails to the GMAIL. The GMAIL is set up on my phone now.

I went and tested this by sending an email from each of the AOL and webmail to the other one, and they both sent just fine. The AOL->Webmail one showed up in my GMAIL inbox on my phone, but my Webmail->AOL one is not sending to the phone, or to GMAIL.

I love everything about this phone, but am starting to miss Blackberry email app because it never deleted emails from the server.

Any ideas?