Here's my (rather shoddy) try:
![[Image: attachment.php?pid=950786]](http://shoutbox.menthix.net/attachment.php?pid=950786) 
Just a simple matter of turning the tab image into an alpha mask, then using it on the gradient box. Not too sure about the border though. I guess a lot of things still can't be done in PdN and I don't know too much about Photoshop. Also, the box's border is clipped anyway, so I have no idea what colour it'd be, if you want to be picky 
 
EDIT: accidentally saved without alpha channel 
