InfoPath Dev

We have a rest web service which I am trying to use. The only web service I have used previously is the  standard User Profile one in AD/shairepoint

 I try to add a data connection but if I put in the url of the web service I just get an error that the address is not valid, then that it cannot access the service.

If I browse using internet explorer it is a valid url.

So how do I use this sort of web service in infoPath? Can it be done? 

The Web Service needs to use document/literal style encoding.  InfoPath can consume only document/literal style Web services.

Thanks, sorry to appear dumb, but what web services fall into that category?, If I were to write one, exactly what would the output be. I have very little experiences of web services -  years of standard asp, then aspx for in house database applications, nothing much else till infopath