Erik,

Here is my viewpoint:

"OK, you want me to learn a tool that is not in widespread use. Therefore, I will be hurting myself by learning a tool from Borland, a company that noone knows if it will be here tomorrow. So, my rate is DOUBLE my VFP rate."

Erik, you are a consultant/contractor, not a WARM BODY. This guy sounds like a broker trying to milk $$$ out of you. Maybe you should terminate the relationship.

Sometimes walking away from a deal is the best "thing to do".

Only you know, but do not let him sucker $$$ out of your pocket.

Heck, everyone is learning a product every day anyhow, new releases come out so frequently that "there are no experts". So, he either needs your skill or not.
If you take the lower rate, I believe you will see the relationship go sour very quickly "People do believe they get what they pay for".

It's your customer, and your call. He needs you, not you need him!

I am reminded of the story "Fountainhead" where Howard Roark says "I do not build to have customers, I have customers in order to build".

Good luck and stick to your gut feel, you are worth more than you know.