Domain Mapping conflicting with Events+

we're running events+ and domain mapping on a multisite install. currently, the rsvp list is not working properly. events+ uses admin-ajax.php to query the list of rsvps, but since we are using the domain mapping plugin, it is denied access, because (apparently) admin-ajax redirects back to the original url of the site.

so for example:

when we created a new site, url was: site1.multisite.com, and we domain mapped to blog.somewhere.com. the rsvp button tries to call http://blog.somewhere.com/wp-admin/admin-ajax.php?action=eab_list_rsvps&pid=17, but is then redirected to site1.multisite.com.

i suppose that since the domain names are different, as a security feature, access is denied somehow.

any help on how to solve this would be great. i have already tried updating wordpress options siteurl and home, but this creates more problems.

anything......?

thanks.