When you pass is the SMTP Server Name add + ";;" + user$ + ";" + pswd$
Example:
CALL "*web/email",ERR=SEND_HTML_ERR,FROMADDRESS$,
"",TOADDRESS$,CCADDRESS$,BCCADDRESS$,SUBJECT$,
MESSAGE$,ATTACHMENTS$,OPTIONS$,SMTPSERVER$+";;"+user$+";"+pswd$,
0,0,BODYENCODING$,ERASEIT,ERRORMESG$,SENTDIRECTORY$,SAVEDFILENAME$
This will pass the userid and password specified to the SMTP server.