If you create an account with Plesk for
www.myblog.com, and install Wordpress to it, give the address
www.myblog.comIt doesn't matter that
www.myblog.com is actually hosted elsewhere on a cPanel server - if you set the hosts file on your PC to look at the Plesk server's IP address, you'll see Wordpress on
www.myblog.com coming from the Plesk server: you don't need to use a temporary address.