Hi Kevin,
Not sure if this is what you need, but have you taken a look at the X10 Firecracker Program.
This contains at least some hints to your question.
I asume you need something like:
var my_X10_mod = Modules.WithName("A4");
my_X10_mod.Level = 35;
I have no way to test it, but in ZWave it does work.
Cheers Louis