This might help. Email this company and ask for instructions. I think Michigan might have cold winters and warm summers like the UK so they might be able to help you. www.ashwoodnurseries.com and this one also http://www.burncoose.co.uk/site/plants.cfm?_cr=GY1,442835&pl_id=1476
They both have great information on the Daphne you describe.

Daphnes are some of the easiest shrubs to grow, but only if they like you and their situation! I stock a few, but each year the available stock is reduced, as are the varieties. Unfortunately, because of the demand for such special shrubs is so high, some growers produce rapidly grown plants that just aren't tough enough to withstand conditions when they're planted out. The old propagators who produced plants from cuttings, taken during a 'window' of opportunity in late spring, supplied stronger plants, but more slowly. Microprop. has, I think, failed the plant, and frailty and disease are not uncommon.

Daphnes really are very easy to grow if the growing conditions are right. I have thought that with Briggs Moonlight, it benefited from a bit of shade and pine bark mulch. Some people have said it is not reliably hardy here but I know that it is because I have seen them grown for years under a stand of pines. I think buying them in large containers is a mistake and that daphnes really need to be planted when they are smaller since they dislike growing in pots or being disturbed. That is an interesting way of looking at it, I never looked at it from a grower's point of view. Microprop. is great for some shrubs that cannot easily be produced through cuttings (mountain laurel) but aside from that I don't know a whole lot about it.