My question is similar to this. How To Pass Soap Header When WSDL Doesn't Define It? But is different.
For a web service I use, all methods need authentication w
Key for me in using this question to help myself was recognizing (as some pointed out) that the headers in question are those of WS-Security standard.
If your proxy generating tool is "custom" it seems logical that you might have a switch to automatically add the headers for WS-Security. However, if you're using WSDL.exe ("Add Web Reference" in Visual Studio), consider svcutil.exe instead ("Add Service Reference").
If you use a WCF proxy, you can override the given config and allow WCF to add the headers for you:
From there you can specify the password:
RemoteSvcProxy.TheirClient client = new RemoteSvcProxy.TheirClient();
client.ClientCredentials.UserName.UserName = "uname";
client.ClientCredentials.UserName.Password = "pwd";
I don't know what your custom tool is, but perhaps the framework it's based on also has similar configuration options.