can't use it

Fireworks doesn’t officially support setting different opacities for fills and strokes, but here are two workarounds:
- Stroke less opacity than fill: Use effects / Photoshop live effects / stroke, set opacity accordingly
- Fill less opacity than stroke: Re-create the solid fill using gradient fill with 2 same colors, then use gradient fill’s opacity sliders to decrease fill opacity. This will not affect the stroke.

Solution: install the Fireworks CS4 upgrade from Adobe’s website.

Adobe – Fireworks Support Center : Downloads : Updaters

Then Fireworks will start crashing after quitting, but that’s not such a big problem :)