Trouble with "Send As:" function in IMs?

Lately, when I IM a Contact on my Messenger List and I choose the ID I want to use under the Send As Function it doesn't seem to work. My ID is showing up as my Primary Profile Name and not under my other aliases. I have tried rebooting and it will let me scroll down to whichever name I want to use, but when I type my message the ID I have chosen is NOT the one that appears beside my message. Hmmm...any ideas why this is happening and what I need to do to fix it?