Sell the Punters an Aer Lingus ticket, show the flight (codeshare or otherwise) as an Aer Lingus flight, you must live with the consequences/fallout.
If I was a punter, methinks I would read VERY carefully who was ACTUALLY flying me from A to B (or more likely Z) and take a train/rental car as appropriate on occasions, but, the punters don't. So. . . . . Caveat empo. . sumfin or another.
Harsh realities of aviation in 2011.