Should be something in the line of...
:xeq /SAMBA/PUB/bin/smbclient "-M yourPC -I your.pc.ip.addr"
Type your message here or redirect input in above line.
:eod
The "-I your.pc.ip.addr" should only be neccessary if your
3000 cannot resolve the nodename "yourPC" properly.
All this is "by heart" only; haven't test-typed it right now.
Lars.