Sorry, let me explain. I basically went to /path-to-bbpress/bb-templates and copied header.php, footer.php and style.css to my desktop using ftp.
Then I created a folder in the main root /path-to-bbpress/my-templates/
Basically, bbPress will try and see if there are any files in my-templates and use them without changing the original template files in bb-templates. Great! If you make a mistake, you just delete your file out of my-templates and it uses the original again!
Anyways, I made changes to header.php to make it look like the first part of my WP template I was trying to use. The basis CSS elements like the header image, the different div's that the Wordpress page uses. I looked at 'the source' of the WP blog and used that code. When I was done editing that file, I uploaded it to /path-to-bbpress/my-templates/
I then did the same with footer.php and then changed colors and added some of the extra fields required to style.css to show up like WP.
Not trying to say this is easy, but there are some pretty good documentation posts in the bbpress.org forum if you want to do some searches.
Sorry, not much help, but I was forced to do this when I couldn't get the include of WP to work in bbPress. If someone can tell you how to do it easily, (say through a page) then maybe research that some more.
Trent