Walter, I can't comment on the Netherlands but in other jurisdictions, if your distributor screws up but has a good customer contract limiting liability, the customer may sue you instead of or in addition to the distributor.

You might consider a simple, one-page enduser agreement that becomes an Appendix of your distributor's customer agreement and is signed along with it. It simply states the conditions under which you can be held responsible and the limit of your liability. As long as you make the remedies and liability limit reasonable (and your lawyer will be able to advise you what "reasonable" means), Courts will pay heed to such agreements. Or so I'm told!

I know you're doing well, so it might be worth paying for an hour of a top commercial lawyer's time- I say "top" because an hour of such a lawyer's advice is far cheaper than cautious hedging from a lawyer whose hourly rate is less, but who expects to be paid to "investigate" areas of the law with which he/she is not familiar.