apache / svn custom authentication using custom module

Question

I would like to set a svn server where some user can have access from local area network only and some special user who can access using internet / wan.

I could not find any way to do the above so started with custom apache2 module for authentication.

Here i use

ap_hook_auth_checker(helloworld_check_user_access, NULL, NULL, APR_HOOK_MIDDLE);
//and 
static int helloworld_check_user_access(request_rec *r)
{
   return HTTP_UNAUTHORIZED;
}
//and
AP_INIT_FLAG("HelloworldAuthoritative", ap_set_flag_slot,
    (void *)APR_OFFSETOF(helloworld_config_rec, authoritative), OR_AUTHCFG,"" 
...

the dav_svn.conf is

<Location /location>
   DAV svn
   SVNPath /path to svn
   HelloworldAuthoritative On  // defined in my hello world module
</Location>

after setting up the mod, the sever simply ignores it and shows the list of file when i browse the server, any suggestions!