JPS,
The information came from a letter sent to Aspen Tree Expert Co. Inc (Mark C) on the 24th July 2003. The letter was in direct response to the concerns generated over butterfly modifications and the information in my post was the detail within the letter.
The information provided within the letter does only apply on produced items up to July 2003, so basically they are saying that modifying a harness in the ways described on a brand new harness is not acceptable.
I understand that climbers may need this documentation for there chapter events, and the new ITCC rule change will mean that any mods will require a letter from the manufacture to state its' suitability, that is of course unless your system incorporates the existing bridge?
But i am unsure as to whether the documentation i have would still be valid, you may want to check with MC on this one or even Tom D may have a comment to add.