if that doesn't help, it would be lovely if you could post some screenshots of the distortion so we could see exactly what is happening.

the stretching on slopes can't be stopped on terrains coz they're always textured from above. if you use a MDL instead of a HMP u could probably use some fancy unwrapping tool (blender is a wonderful modelling program and has a nice LSCM unwrapper) to texture it fairly evenly with minimal stretching.

hope this is helpful!

julz