GetMsgProc

Im using a GetMsgProc hook to trap a message something like

Code:

#define USERDEFINED ( WM_USER + 31758 )

DllExport LRESULT CALLBACK GetMsgProc( int ncode, WPARAM wParam, LPARAM lParam )
{
     MSG *lpmsg;
     HHOOK hhk = 0;

     lpmsg = ( MSG * ) lParam;

     if( ncode < 0 )
	   return( CallNextHookEx( hhk, ncode, wParam, lParam ) );

     switch( lpmsg->message)
     {
          case USERDEFINED : // do stuff
     }

     return( CallNextHookEx( hhk, ncode, wParam, lParam ) );

The WM_USER + 31758 message occurs when a string is received by the application. I should point out that the application is a chat client and the string is coming from the server.
My question is, is it possible to get the string with the information I receive in GetMsgProc?
I've tried using the wParam's in various ways but cant get anything to work correctly.