About 4 weeks ago i put 3 cuttings from an old rose bush that i think has been growing outside my apartment for about 40 years straight in the soil and put a plastic fruit juice bottle over it for protection. I've been watering it every couple of days and it is growing really well! Apparently it's best to cut off any leaves as they start growing so that the cutting can concentrate on developing the root system. After about 4-6 weeks you should be able to remove the plastic and it'll be fine! I'm only guessing here but i kind of think of antique or older variety roses as being more hardy than the newer varieties so you should have no problems. The only further advice would be to make sure it's not getting TOO much sun, it's getting towards winter here in Australia and even with the small amount of sun there is still quite a lot of condensation that gathers in the plastic from the heat of the sun. So if you're in the northern hemisphere and summer's approaching you might want to make sure it has some dappled light during the hottest part of the day so the cuttings don't get scorched, maybe put a pot plant in front of it just to make sure... Hope this helps, i'm only an amatuer gardener but was so excited that my haphazard planting method worked that i wanted to share it with someone! So if you are an experienced gardener then you probably know most of this info already!

I haven't worked much with old roses though, I don't believe that they are harder to root then the newer varieties. Most of them were propagated from cuttings as grafting (if I am remembering correctly) became the prefered method of propagation after 1850.