If you have the 1300 struts then you should be able to get old Golf inserts to fit (this is a favourite with the american owners but I don't know anyone in the UK that has tried it for themselves).
If you have the 1500 struts then it is a lot of work to convert them to inserts. Be prepared for some serious graft!
You may find it cheaper and easier to get some made by a specialist (don't quote me on the cheaper bit though). Koni list them but unless you pay up front for a full production run (20 sets I think) then you are out of luck and they are very reluctant to do it in the first place.