DataSet->ReadXmlSchema and Proxy server

[Greg]

I'm trying to use the ReadXmlSchema method of the DataSet class from behind a firewall/proxy server and can't get it to work. I can run the code on a machine not behind the firewall and it works fine, but I can't figure out a way to get ReadXmlSchema to use a Proxy

This works with no proxy server but gets a (403) error when run behind the firewall
myXmlReader = new XmlTextReader(schema)
myXmlDataDocument->DataSet->ReadXmlSchema(myXmlReader)

This gets a (407) Proxy Authentication Required error, closer maybe, but still doesn't work
NetworkCredential *nc = new NetworkCredential(S"username",S"pwd",S"domain")
WebProxy *myProxy = new WebProxy("http://proxyserver:port",true)
myProxy->Credentials = nc

GlobalProxySelection::Select = myProxy

myXmlReader = new XmlTextReader(schema)
myXmlDataDocument->DataSet->ReadXmlSchema(myXmlReader); // does this not use the GlobalProxySelection??

Any suggestions?