I'm using authcache module with domain access module in a drupal 6.22 installation and encountering a couple of concerns. First my site has a personalized block for authenticated users, I followed the documentation coupled with the authcache_example module for implementing this functionality which requires considerable logic and calls to many core drupal and custom functions. When using a drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL); in the function within the authcache/ajax/authcache_custom.php so that I could invoke the block directly with module_invoke the authcache footer from the register_shutdown implementation of authcache's hook_init (<!-- Authcache Footer JSON -->) is appended to the json response and therefore the corresponding javascript function is not called with the ajax response. Including the respective files such as common.inc, path.inc and the custom module files however does not cause the footer json to be appended to the response, though is excruciatingly painful.
Another trouble that occurs is when authenticated users submit comment forms under the node page the message Validation error, please try again. If this error persists, please contact the site administrator. generated from the drupal_validate_form in forms.inc. Disabling the domain access module seems to resolve both of these concerns.
I'm assuming most of this is caused due to domain access module running its own bootstrap phase before other modules are initialized as it needs to create some of the global variables for node access permission, url alias generation etc. Some help or pointers on how to overcome this issue would be greatly appreciated as my site can't live without either these two wonderful modules.