I just dig out the suckers trying to keep as much root as I can, pot them up over winter and replant in the spring.
Really really easy to propagate this way.
Christy you are quite right they don't sucker like normal raspberries and are far less invasive. So the other tips of digging up suckers with roots don't work.
So what I did is when I was pruning it I popped the cuttings into the some nice soil nearby and am waiting to see which take. Everything is dying off right now so hard to work out which are going to take until spring. Fingers crossed.
Wish I had known your tip earlier I'll go and see if there are any branches I can try your idea.