Int 15 Fn 12  - Topview - Send Message - "setname" - Assign Name To Mailb  [Q]

   AH = 12h
   BH = 11h
   BL = mailbox to name
       00h DWORD on top of stack is mailbox handle
       02h use given task's mailbox (task's handle on top of stack)
       03h use current task's default mailbox
   STACK: DWORD length of name
          DWORD address of name

See Also: AH=12h/BH=12h"GETNAME",AX=DE0Eh