Outlook not saving sent items in some configurations

[TheBundo]

I have a Yahoo email address, and send mail using smtp.sprintpcs. My sent mail is saved in sent items, just like on a computer. But with the dropping of Sprint's email approaching, I set up my account again using the "automatically get settings" feature (called something like that). Mail comes and goes fine, but my sent items aren't saved on my Mogul, even though the box is checked to save a copy. However, a copy is saved on Yahoo mail online, in a folder called "Sent Items" which is different than the usual "Sent" box, which is where items are saved when sent from a computer logged into Yahoo mail.

I can't figure out why they don't save on the phone using Yahoo as the sending smtp