newbie SKILL question: how to create a via

Hi everybody-- I'm writing some SKILL code to layout an adder. I need to place some vias to go from a metal 2 layer to a metal 1 layer, but I can't figure out how to do this. In the interactive layout, I'd just click Create-->Via (I'm using Cadence 6.1), and select VIA12_A and the other parameters, and then click where I want the via. But, looking through the Cadence docs, I can't seem to figure out how to do this with code. I found the "dbCreateVia" function, but it needs "d_viaDefId" for the second parameter, which I can't seem to get without first placing another via by hand and using the dbFindViaHeaderByName(cvid "VIA12_A") function. I'd like to do this without having to have that extra via to begin with. Thanks! -Chris