My clever widget backlink strategy not working!

So I have a pretty good niche blog that just sells some affiliate products, mostly shoes, and I came up with a really clever way to get site-wide backlinks from other relevant blogs.

I made a widget that fulfilled a need for many websites of the niche and I got it on several websites. It's just a snippet of html code they add to their sidebar and it puts an image on their site that when clicked will load a page from my site in a slick looking "shadowbox" iframe.

Everybody really loves the widget and I've got about a dozen sites who have put it up in their sidebar. In Yahoo site explorer I have about 4000 backlinks, mostly from the widget linking to that one page it loads up on my site. Every single post on their blogs has that backlink to my site, including all the new ones, and these blogs are updated daily.

I was hoping that I'd get lots of link juice from this setup, but today when I checked Google Webmaster Tools (for the first time ever, though my site has been up for a couple months), I was surprised to see it listed only 211 backlinks, and none of them were links to my widget page! Not even one!

Does anybody know why Google isn't counting all these links? They are from really credible websites that are indexed high by google. Does google think my widget links are spam? Or is there something wrong with the shadowbox javascript library that stops google from following pages loaded by shadowbox? The link to the page on my site is in an "a" tag followed by rel="shadowbox". Maybe I need rel="dofollow;shadowbox;"?

Thanks for your help, I really hope I can start getting link juice from this widget somehow.