howto firmata pulseIn? (as3glue, firmata, SR04)

Hi All,

I'm new to using Firmata. I'm trying to get a reading from my SR04 sensor into Flash. I'm trying to figure out what firmata's equivalent is to the Arduino's pulseIn() function. After searching for the last hour it didn't really seem like there was.

I figured I could just mimic the pulseIn() function, somehow, but I couldn't find out how it does it's thing.

Is there anything I should know about before I start modifying the StandardFirmata sketch to see what works?