Accessing SSMS 2008 R2 results pane via extensibility add-in

Hi

I'm trying to write an add-in into SSMS 2008 R2 using Visual Studio 2010 extensibility project.
What I am wanting to do, is allow the user to right click on a cell in the results showing in the query results pane, pop-up a context menu and from these menu items execute further queries based on the value in the cell selected.
So far I have successfully created an empty add-in that does load into SSMS - I say empty, as I know it loads, but has no other functionality.
Can someone point me in the right direction as far as what SQL libraries to look in  to gain access to the results pane?

Thanks
Rod