OK, me again, and still having trouble because I'm working on two niches at the same time. I set up posterous for my first niche, sending them the email from my specific gmail account for that niche, no problem.
I then log into my other email account (gmail) for Niche 2 and send the email to post@posterous. Somehow it defaulted to my Niche 1 posterous account. So then I tried to set up a new space on posterous, with the name Niche 2. That worked except that the bio is still the one I created for Niche 1, so the information and link is to my first niche.
How can I create a separate space or account on posterous for Niche 2 so I can set up the bio specifically for that?