WTSQuerySessionInformation on VPN - c++

Question

We are trying to write a C++ DLL that would run on VMWare server and would return the client (terminal user) IP Address and name.
I am using WTSQuerySessionInformation to fetch the IP Address. The problem is when I am running from within the company's network, the DLL returns the exact IP Address which maps to an appropriate HostName.
But when I login from home to the company's VPN and try the same, it gives me a different IP which doesn't have any DNS Name.
LPTSTR ppBuffer = NULL;
DWORD pBytesReturned = 0;
PWTS_CLIENT_ADDRESS pWTSCA = NULL;
WTSQuerySessionInformation(WTS_CURRENT_SERVER_HANDLE, WTS_CURRENT_SESSION, WTSClientAddress, &ppBuffer, &pBytesReturned);
pWTSCA = (PWTS_CLIENT_ADDRESS)ppBuffer;
String^ addrStr = String::Empty;
for (int i = 2; i < 6; i++)
{
addrStr += Convert::ToString(pWTSCA->Address[i]);
if (i != 5)
addrStr += ".";
}
Is there a way to work around this problem? Am I following the right approach, or there is a different way of doing this?
Edit:
If I use WTSClientName, it return the IP address separate by hyphen (like W-X-Y-Z). Could you please help me understand if I have done anything wrong here? Here is the code:
LPTSTR szClientName = NULL;
DWORD dwSize = 0;
String^ cliName = String::Empty;
if (WTSQuerySessionInformation(WTS_CURRENT_SERVER_HANDLE, WTS_CURRENT_SESSION, TSClientName, &szClientName, &dwSize))
{
cliName = gcnew String(szClientName, 0, dwSize);
}
return cliName;