FIX Market Data Request - what to use for Symbol

According o the newly available cTrader FIX Engine, Rules of Engagement (Version 2.5)  you can connect to the price feed and request a Market Data. When i attempt this i get a FIX Reject 58=For input string: "EUR/USD". 

I tried this with EURUSD but got a similar message

I have written FIX connectors before and the symbols are usually defined by the platform

The FIX document suggest sending a "Long" ??? with "Instrument identificators are provided by Spotware" (p8) , but no such identification is in the document or as far as i can see on the spotware site

Please advise on what we should use for Symbol 

Here is my fix request and response

<20160804-03:24:12, FIX.4.4:icmarkets.xxxxx->cServer, outgoing> (8=FIX.4.49=12035=V34=249=icmarkets.xxx52=20160804-03:24:12.22556=cServer262=1263=1264=1146=155=EUR/USD267=2269=0269=110=080)
<20160804-03:24:12, FIX.4.4:icmarkets.xxx->cServer, incoming> (8=FIX.4.49=10335=334=249=cServer52=20160804-03:24:12.24656=icmarkets.xxx45=258=For input string: "EUR/USD"10=131)

My code is quite simple: (where symbol is a simple string
 

        MarketDataRequest request = new MarketDataRequest(new MDReqID(""+nextMdReqId++),
                new SubscriptionRequestType(SubscriptionRequestType.SNAPSHOT_PLUS_UPDATES),
                new MarketDepth(1));
        
        NoMDEntryTypes bidOffGrp = new NoMDEntryTypes();
        bidOffGrp.set(new MDEntryType(MDEntryType.BID));
        request.addGroup(bidOffGrp);
        bidOffGrp.set(new MDEntryType(MDEntryType.OFFER));
        request.addGroup(bidOffGrp);

        MarketDataRequest.NoRelatedSym symGrp = new MarketDataRequest.NoRelatedSym();
        symGrp.set(new Symbol(symbol));
        request.addGroup(symGrp);

        Session.sendToTarget(request, sessionId);