How to jump cast easier?

Other than what's suggested like using G5 keyboard's macro function, or using key mappers/tweakers which I doubt will allow you to input two keys on on button, you're out of luck. You probably have to write your own program/emulation for this since it's rather unique to specific usage. Plus I bet the existing remappers will make it override in the registry or global setting so when you're not playing maple, your keys are going to be messed up, just easier finding other alternatives or using those already suggested.

Well my keys are already remapped. Caps lock doesn't exist on my keyboard, for example.

Whatever. I'll just practice. I just don't want to be caught jumping into a mob when i should have been DSing them.

A suggestion is having the jump and DS keys in a letter and like alt.
For me, jump with S and DS with Alt is really easy. It is all about practice though, you get used to it.

I saw on Basil (ohthehorror) a guide on how to do this: http://www.basilmarket.com/forum/862479/....html#Keys

I would add that putting the jump key to the left of the skill is much easier than the opposite. I always move strafe when I'm doing Bodyguard A. Using a soft plastic cover might decrease the friction and help with the timing.

If you get used to it enough, it shouldn't bother you too much. It's not like jumpcasting is a required player skill; it's more of a leg-up for jobs with slow movement.