[Serusers] multiple domains

Hi all, here is my problem when i use serctl to add a account the domain name is extract from email address and insert to domain field of subscriber table. I added two domains (support.example.com and example.com) but if i use digest authentication (!www...) the client send is domain and SER look at its subscriber domain field so it's right for example.com's clients. I have to change domain name in subscriber table for all support.example.com's clients or don't use digest authentication! is it possible to avoid changing domain field of subscriber table for accounts of others domains? What about dns srv may I have to add srv recording for each domain or using outbound proxy? Regards Harry