It's a challenge only in that you need high light (3 watts/gallon), a decent substrate, CO2 injection, ferts, and patience. Here's a good reference for the planting part: http://www.nature-aquarium.com/glosso.htm
Glosso's not really that hard. It doesn't even need that much light. I've had some of the best glosso I've ever grown under 2.0wpg. It does need good nutrition and CO2 though. Given that, and a smaller grained substrate it'll grow really well. I think the original challenge came from the fact that we didn't have that much experience with plants as a nation/group when it came onto the scene and a reputation stuck with it. Given nutrition and CO2 that stuff's a weed.
The hardest part about it is planting. It does much better if planted in small bunches, 2-3 plants per bunch, rather than as a single large clump. It takes a lot of patience, but if you can stick it out it'll reward you.
Onyx helps! It's much easier to plant becuase the granules are soo small. Like Phil said, it would be great to plant in small punches, but if you don't have that much, you can cut them up in to individual plantlets(should have about 2-3 leaves each) and plant those instead. Onyx will still be able to hold them down.
Now if you have low light, expect glosso to grow upwards. If that does happen, keep chopping and replant. Eventually the glosso will train itself to grow out. If you have high light, expect the glosso to grow out instead of up. I had a friend who had an Ah supply 55 watt straight on top of the glosso in his 20 gallon long tank. When I saw the growth of the glosso, I started laughing, because it seemed as if the glosso was growing in to the substrate becuase the light was sooo high. Though that was funny to share. Good luck with your glosso growth!