samba - Nov 1998 - Connecting to Samba from an NT service

Dear all,
     
     for reasons which I won't bore you with, I need to be able to connect 
     from a program which is running as an NT service.  I have modified the 
     service's startup parameters to contain an id/password combination 
     which is valid at the Samba end (Solaris 2.6 Samba 1.9.18p8), but I 
     cannot get connected (and of course there are no messages).  The 
     connection is defined as UNC.
     
     If I try the same combination manually from explorer or a user-type 
     program, all is fine.
     
     I can successfully connect to similar UNCs pointing at Novell and NT
     shares - the only ones that fail are the Samba ones.  I am using 
     USER-type security which seems to work for everything else and I DO 
     have EnablePlainTextPassword set, because all the user-level 
     connections work.
     
     Can anyone suggest where I should look ?  Is this possible at all ?  
     If I need to start debugging the Samba setup, can someone suggest some 
     reasonable debug settings ?
     
     Thanks in advance,
     
     Maciej Chodzko-Zajko