I just bought an Impatiens flanaganae and divided it up. I thought I'd post the pictures in case anyone is curious what it looks like.

I got the plant at Annie's Annuals and Perennials in Richmond, CA. I think there may have been one or two more, but you really have to dig in the back under the benches to find them. When I bought it, the employee was not aware it was being sold. It was $19.95 in a 1 gallon pot. The pot was severely distorted by the tubers.

My initial hope was to remove the growth on the left with a bit of tuber, and also separate the small almost spherical tuber at about 2 o'clock (this also has a tiny shoot). My original plan was to replant the other big shoot and the bulk of the tubers into a big pot...

Here are a few views of the plant once I cut the pot away:

Unfortunately the pieces did not break apart as I planned. Here's what I got:

The pieces numbered 1,7 and 8 all have tubers plus shoots, as does the small tuber number 5. The separated new growth (number 2) has roots, so hopefully all 5 of those will make it.

I doubt the shoot fragments (3,4,6) will survive, but I'm willing to be surprised...

It will be interesting to see whether the tubers without obvious growth (numbers 9 and 10) will send out shoots. If so I could get as many as 7 plants out of this.