Yahoo messenger/chat

I'm having a problem with yahoo chat that I hope someone might help me with. I have SBCyahoo DSL. I had been going to yahoo chat through my sbcyahoo home page. I would then select a sub account name associated with the name and profile I wished to be seen as in chat from a drop down. Unfortunately I made a mistake when signing up for my account and used my full real name as my account name so selecting this sub account name is critical for maintaining anonymity.
The problem with going to chat this way is that it sometimes takes 7 or 8 tries before i can get to the room I want, the text box is way too small (approx. 1 1/2" high), I frequently lose features like sound or mic and have to leave room and reenter.
Today I was told by another chatter how to use yahoo messenger to enter chat. When I selected yahoo chat from the messenger list a notice came up telling me that my main yahoo I.D. was how I was logged in and if I wished to use a different name to chat I needed to set my alternative name as default. I did this and was able to more easily access a room, had a much larger viewing windoiw, had no problems with voice chat whatsoever.
Tonight I followed the same procedure and was shocked when everyone started speaking to me using my real name. Although I saw the alternative nic name I had selected on the room list, whenever I spoke my main account I.D. showed up. The profile was blank except it contained my main I.D. at the top with the name I wished to use listed as nic name. No other profile details. I contacted SBCyahoo support and they told me they had nothing to do with features like chat and I needed to go to yahoo directly. I could find no help there. So much for Yahoo protecting my privacy. Can someone help me get this straightened out?