Publish XP - how to modify install_registry.reg file?

I have gallery embedded in drupal as a multisite installation. Therefore, the URL from which the install_registry.reg file is downloaded for Windows XP publishing is not the URL that should be added to the registry. Specifically, the downloaded file has:

"href"="http://www.site2.com/index.php?q=gallery?g2_view=publishxp.PublishXpLogin"

but it should be:

"href"="http://www.site1.com/ms_gallery2/site2/main.php?g2_view=publishxp.PublishXpLogin"

This is fine for me, since I can go into the registry and change it myself. But the attractiveness of the publishxp module is that it is easy for the less computer literate to use. So, can anyone recommend a way to alter the module so that the install_registry.reg file that is downloaded is correct for both sites?

I figure I need to change this line in DownloadRegistryFile.tpl

"href"="{g->url arg1="view=publishxp.PublishXpLogin" forceFullUrl=1 htmlEntities=0}"

but that's about all I understand at this point.