Unidrv Minidriver and HCT 12.1.01

Hi,
I've just finished porting and testing a W2000 printer minidriver
(unidrv). When I run the WHQL tests (ie. HCT) I pass every test but the
"x64 Calling Convention" test.
That test requires to name the path of an executable driver, and that's
the point where my problem starts.
Since I only provide a simple GPD file (and the INF file) I do not
have any 'real' driver.
My first guess was that I should use unidrv, but when I set the second
parameter to point to unidrv.dll, HCT test logs states that unidrv has
(obviously) no debugging information.
Where am I wrong or should I wait for an errata?

Confused and clueless,
Patricia