& character in soap URL

Hi Experts,

I have a scenerio in which the flow is

WS..>SAP PI...>RFC.

The interface is running successfully in SOAPUI

But the problem is when the 3rd party is trying to consume the same WS it's giving  an error:

forbidden access- 403

The 3rd party is saying that the special character as in  "&" is getting converted to "&lt"..and thereby they are unable to hit the WS.

Can i convert the URL ..so that it becomes without special character.

http://xyz:abc/XISOAPAdapter/MessageServlet?senderParty=&senderService=bc_ginger_sender&receiverParty=&receiverService=&interface=Si_Guest_Details_Scheduler&interfaceNamespace=http://Sample.ginger.com/Guest_Details_Scheduler