I have a customised Sharepoint results xsl, and I've added new columns before (via Metadata mappings etc), this one has me stumped. We have a document type, that can either be a 'Document' or a 'Link to a document'. When I search I want to check the URL INSIDE the 'Link to a document' (what it points to), but I only get the actual URL for the 'Link to a document'.
What property do I need to be indexing to display this?
It seems like you are asking for a feature that dynamically indexes the contents of the 'Link to a document' URL. If true, unfortunately this can't be done with out-of-the-box SharePoint. The product only indexes a set list of URLs / content sources as specified in Search Admin.
As a custom solution, you could write your own indexer using a timer job that regularly extracts the contents of each 'Link to a document' URL column and stuffs it into a field in your document content type. Perhaps there is even a way to run SharePoint's indexer over it and use the results of that.