XLM API get domain from Session ID or Login name

hi,
i need the customers domainname but i have only the session id and the customer login name

<packet>
<session>
<get/>
</session>
</packet>

result:
<session>
<id>f15cabb0a544df13aee1ee5b55de0530</id>
<type>JimmyJoe</type>
<ip-address>192.0.2.2</ip-address>
<login>client</login>
<login-time>2007-02-21T23:42:00</login-time>
<idle>2007-02-21T23:43:22</idle>
</session>
how i can get the Domainname from JimmyJoe via API?

thanks
wowi