As a user, I need the Forms tool to run a transform that can merge current DC content during update. The current Form-to-DC transform overwrites the contents of the DC datastream. The specific transform can set in the Forms associations.

1. Devise a method to make the pre-transform content of the DC datastream accessible to the XSLT
2. Preserve the ability to set the specific transform in the Forms association
3. Write one XSLT that merges the existing DC identifiers during execution of the transform