Sent emails show no virtual domains

My setup has both, a principle and a virtual domain (installed via 3.31 gpl) and the accounts are distinct. For some reason I opted not to include domain name to be part of the account names. This also facilitates users to login without the need to specify the domain. The genericstable has got updated; however, mails sent out depict the principle domain instead of the virtual one. Kindly let me know how this can be corrected.

Thanks in advance