The mailing list for listmasters using Sympa

[address@concealed]

I have Sympa running on a machine called lists.terminus.net.au.  It has 
robots set up for virtual domains including lists.au.mensa.org.  This has 
been set up according to directions and is working fine except in one 
respect.  When an email goes to the moderators of (say) 
address@concealed and they reply to it (using the lists.au.mensa.org 
address), Sympa misinterprets it by looking for the list in 
lists.terminus.net.au and it tells them "no such list".  This is what the log 
file shows:

Apr 29 17:20:35 lists sympa[10140]: Commands::parse(address@concealed, 
lists.terminus.net.au, DISTRIBUTE adcom cc97f1ae50e44027f3845ca17c58e757Or, ) 
Apr 29 17:20:35 lists sympa[10140]: Parsing: DISTRIBUTE adcom 
cc97f1ae50e44027f3845ca17c58e757Or 
Apr 29 17:20:35 lists sympa[10140]: 
Commands::distribute(adcom,lists.terminus.net.au,cc97f1ae50e44027f3845ca17c58e757Or,adcom
 cc97f1ae50e44027f3845ca17c58e757Or) 
Apr 29 17:20:35 lists sympa[10140]: Missing directory or config file for 
adcom 
Apr 29 17:20:35 lists sympa[10140]: DISTRIBUTE adcom 
cc97f1ae50e44027f3845ca17c58e757Or from address@concealed refused, unknown 
list for robot lists.terminus.net.au 

Any ideas?