I'm not sure why you would want POP over IMAP. When IMAP is so much more versatile.
Anyways if it works like 10.7 Mail. When adding the account trick it. Do this by just entering some fake email address and password into the boxes and click continue. It will then say it could not find the correct settings, click continue. Now you will be given the option to enter everything manually.
Now you can choose POP and manually enter the POP and SMTP settings for Yahoo. Which I believe are pop.mail.yahoo.com, Port 995, SSL and smtp.mail.yahoo.com, port 465, SSL, authentication required. Enter your correct email address now.
Once added go back to your accounts list and edit it to make sure that it now lists your correct yahoo address and not the fake address in all areas.
Note: Be sure when entering the fake email address to not use a major provider it likely knows. So don't choose @gmail, @hotmail, &c instead use something like @weevilfarts.com.
Thanks! Your mail setup "trick" worked great for me.
Thanks for your recommendation on the POP account setup trick. I am just setting up a mail account on a new (to me) laptop with MacOS 10.8.2. I was having the exact same issue that the boys and girls at Apple knew better and were trying to push me into an IMAP account, when I actually wanted a second POP account.
It's a little convoluted to trick the MacOS, as you must perform several sequential edits to get everything setup, but it eventually worked for me. The Apple Store Genius guys in the Reno area were clueless a week ago on how to do this, so thanks again for the work around instructions.