does NATd _prevent_ use of stateful ipfw rules w/ keep-state?

[OpenMacNews]

In continued digging for some guidance w.r.t. my earlier post, I came across the following list comment ...

        > The real show stopper is ipfw with stateful rules using the 'keep state'
        > option does not work when used with the divert/nated legacy sub-routine.
        > What this means is ipfw with stateful rules can only be used if
        > 'user ppp -nat' is how you connect to the public internet.

Is this in fact true?

If using NATd, am I relegated to a _static_ ruleset, w/ no ability to use stateful rules?

Richard