I've tried steel wool previously, but it didn't last long enough too.
I've gone on to experiment with various types of material and found that the following work quite well and will light with firesteel.
1. photocopier paper
2. toilet / tissue / news paper
3. cotton gauze swabs (sponges)
4. Cotton tape.

The trick is to hold the material on the edge of the hacksaw blade striker like charcloth on a flint and strike the firesteel down along the edge where the tinder material is. That way, the sparks will accumulate next to the tinder. Rapid repeated strikes will ignite the tinder in no time....