Hi there - if your stabiliser is a Snakemaster, not one of the equivalent Bulldog or Scott devices then Towsure sell a bracket to use with Swan Neck bars that clamps to the bar, here:
Snakemaster Swan Neck Car Plate from Towsure
However, it states on there also that it won't work with most detachable bars due to clearance of the mechanism, which I can understand having had a few detachable 'bars in the past.
My suggestion would also be to change the hitch on the caravan to an Alko or Winterhoff one with the built in friction pad stabiliser. If you go for the Alko AKS1300 this is not desperately expensive, and these systems are (in my experience) much more effective than the leafscreen type. You can get hitched up much faster as well and they don't squeal when you turn corners. As a previous contributor has said, just remember to keep your towball grease free.
Regards
Dave