Well for Example:
first i add a Domain to my Server 86.59.32.54 ::: 4tel.at
I was able to add a wildcard host entry into an existing domain on my SME 8.1 server using:
db hosts set '*.a.localdomain.org' host ExternalIP '' HostType Self InternalIP '' MACAddress ''
signal-event remote-access update
sv t tinydns
sv t dnscache
NOTE: those are pairs of single quotes indicating empty arguments after ExternalIP, InternalIP and MACAddress
Afterwards I was able to browse to "x1.a.localdomain.org" from my LAN workstations and get the same wordpress site I get at "a.localdomain.org". I don't have any specific host entry for "x1.a.localdomain.org".
You may need to play with .htaccess for the underlying domain to get httpd to behave as you want it to -- I think Wordpress is doing this for me (redirecting me to the desired URL for this ibay).