javascript "Access is denied" error when accessing an external Web service using AutoComplete Extender

I have googled and seen a few posts on this issue but cannot find an answer to it, I think it is because the Service Path is set to a Web Service defined in another project

i.e. ServicePath="http://Server1/ajaxWebServices/Service.asmx"

so how can this be achieved if I need to access an external service?

 
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