Dan,
You can get a list of all SQL Servers in the network using SQL-DMO
and you dont have to be conected to the server.

This code returns all the SQL-Servers.

LOCAL oSQLApp AS SQLDMO.APPLICATION
oSQLApp = CREATEOBJECT('SQLDMO.Application')

LOCAL oServers AS SQLDMO.SQLServers 		
* lista os Servidores disponiveis
oServers = oSQLApp.ListAvailableSQLServers
FOR i = 1 TO oServers.COUNT
	? ALLTRIM(oServers.ITEM(i)), i
ENDFOR

If you dont get an answer for servers in the network, you have to set Cliconfg in DOS prompt,
so set the necessary options in "Client Network Utility", this gives you options to config how the client can "see" the server. It depends on network, firewall, etc...
This way you can use SQL-DMO

Peter