How do I access FOnlineSubsystemSteam instance? Static_Cast Compile Error

Development Programming & Scripting
19

I’m trying to also get this working to access the Steam subsystem, however I seem to be running into the same issues but the static cast doesn’t seem to fix it. I currently use:
The headers:

#include "Online.h"
#include "OnlineSubsystemSteam.h"

Code:

IOnlineSubsystem* OnlineSub = IOnlineSubsystem::Get();
	IOnlineSessionPtr Sessions = NULL;
	if (OnlineSub)
	{
		Sessions = OnlineSub->GetSessionInterface();
		if (Sessions.IsValid())
			//Passed
		else
			// Failed
	}
	else 
		// Failed

FOnlineSubsystemSteam* steamOnline = static_cast(OnlineSub);

I get a compile error on the steamOnline line -
Error 1 error C2059: syntax error : ‘(’ C:\dev\GameTest\Source\GameTest\OnlineGameSession.cpp 52 1 GameTest

The OnlineSubsystem is found fine if I comment out the steamOnline line, and my target.cs and config I believe mirror what it asks you to do in the documentation. Am I missing something obvious somewhere?