samba - Dec 2004 - samba 3.0.9 server is not seen in its workgroup

I am trying to put a Samba 3.0.9 (a Solaris 9 box) in a windows 
network where a W2000 machine is the main server/domain 
controller/whatever. All I want to do is to be able to have the machine 
seen in the workgroup; it can cheerfully ignore the windows users and 
use instead its own users (in smbpasswd and /etc/passwd).  This is what 
I have it set up as (and probably should be changed):

[global]
    workgroup = MCH
    server string = Yucca
    netbios name = yucca
    local master = yes
    os level = 33
    preferred master = yes

When I browse the MCH workgroup, yucca is not there. However, I have no 
problem mouting it by entering its address, as in, say, 
//yucca.somewhere.com/user. Can anyone see what I am doing wrong here?