[Zencart] Changing larger image link

I've used the zencart module to integrate zencart and gallery, but I have a minor problem. I want users to stay in zencart the entire time, and right now if users want to preview an image (click the larger image button under the product thumbnail) they are dumped back into gallery. I figured out that the url for this link is set by the following line of code in GalleryZenCart.class:

$itemViewUrl = $urlGenerator->generateUrl(
array('view' => 'core.ShowItem', 'itemId' => $dataItem->getId()),
array('forceFullUrl' => true, 'forceSessionId' => false));

but I'm not sure how to alter the code to create an absolute path to the image (i.e. sphotos.biz/gallery2/g2data/album_name/image.jpg instead of sphotos.biz/gallery2/main.php...)

Thanks,
Jonathan