Sorry for being late, you're way ahead of me.. which is probably a good thing. Meaning, you got what I was trying to convey. :laugh:
Oh the linky.. I've never done something like this before, so I hope someone can make sure I'm on the level here.
You would have to modify the "tpl_header.php" in the 'common' folder of the default_template. Whereas, I would insert a new folder named "common" into your current template's main folder. Then, I would make a copy of the tpl_header.php from the default_template's common folder. Finally, put that copy into the newly created "common" folder in your current template's main folder.
This is the part I fear I may be wrong. Having said that, you would only have to delete the copied tpl_header.php if something were to go sour.
Inside your copied tpl_header.php, find:
<!--bof-branding display-->
<div id="logoWrapper">
<div id="logo"><?php echo '<a href="' . HTTP_SERVER . DIR_WS_CATALOG . '">' .
I believe it may work like this:
<!--bof-branding display-->
<div id="logoWrapper">
<div id="logo"><?php echo '<a href="www.yourbanner'ssite.com" target="_blank">' .
I believe the "alt" text for the ex-logo is in yoursite/includes/languages/english/header.php
--I actually just tried the above and it works on my end! Using the above tutorial, the new link works fine and it passed validation. Meaning, no code was hurt during this experiment. I like to play the guinea pig, instead of store owners. :D