I think some problems you are going to run into are...
What lighting are you going to use? Most grasses require high lighting.
How are you going to keep the humidity down with watering the plants?
How are you going to remove excess water (water bowl spill etc)
How are you going to be able to properly clean the area?
I am not 100% sure of locality, but I would imagine that the grasslands they are from are pretty dry and the soil very compact. This is going to be hard to replicate.
I would get some nice fake plants that I can bleach every once and a while and then try to replicate the soil.
You may be able to use potted plants which you rotate in and out of the enclosure. I know a lot of zoos do this.
If you can work out those problems then you will have a really nice vivarium for her.