How do I value my B2B SaaS startup based on potential, if I have no paying customers yet?

Value of what? Your time? Or the "company"? Your time is worth nothing. No one is going to invest just so you can pay yourself back wages at some gross hourly rate. The company value is not equal to the hours and cash you've put into it either.
Raise a convertible note for seed stage, debt instead of equity.
Get a job.

**Btw, " We have verbal comittment of funds being allocated waiting for corporate approval"

Is worth squadoosh. You sound like you're fresh out of college or something, but the corporate world is filled with promises and slow moving parts.

its very very hard.

borrow money and get yourself to market.

get some revenue moving then you can sell equity for a lot more money.

no doubt you need to consider whether you have done enough to plant his business...if you don't understand your value...its because you probably can't yet:

price your product

figure out how to do sales

have protected your intellectual property

gotten sufficient buy-in from friends and family.

you need a strong business plan and proforma....

Value is based on what an investor is willing to pay. It's a negotiation process, an auction process and in varies depending on deal terms.

Are you selling common stock or preferred?

Participating Preferred?

Are the investors Friends and Family, Angel's, Strategic, VCs? Each will value you differently.

http://drivenforward.com/blog/raising-capital-cookbook-valuation

http://drivenforward.com/blog/raising-capital-cookbook-valuation-aint-all-that