[GRASSLIST:5588] v.to.rast and null values

Hi,

I have a point vector connected to a postgresql table. I want to create a raster from the vector using values from one of the columns and so I can use:

v.to.rast behr_grid column=total_richness output=total_richness

This works fine _except_ that the psql column contains both 0 and null values and the null values come through into the raster as zeros. Is there an easy way to get it to recognize nulls? I can always update the table to set NULL to -9999 and then use r.null, but I wondered if it was possible to preserve the nulls in the first place.

Cheers,
David