Hi Ram,
Only unique elements can be promoted and two elements *cannot* be promoted to create one unique field 'out of the box' – have a look at for more information http://msdn2.microsoft.com/en-us/library/aa561059.aspx. I think you could probably fudge something with distinguished fields
but I doubt it'll be supported by Microsoft, but properties promoted in
a custom pipeline component from a combination would be possible
If you need to read read the value of a repeating element in an orchestration, you'll need to dive out to XPath in an Expression shape.
Hope this helps,
Nick.