Question about signing drivers

Hello,
I’m developing intermediate driver and I want to provide signed cat file for
it’s release version.
For test purposes I created (and installed) my own “test” certificate which
serves me as
“trusted publishers” certificate. When I tried sign my driver’s cat file
with this
certificate and then install this driver into PC, all works fine. No alerts,
no problems.
Driver was successfuly installed. And my questions is: Can I make
installation application
which at first place install my own certificate (for example “MyCert.crt”)
into user computer
(of course with user awareness) and then tries to install my intermediate
driver which is
already signed with this certificate (“MyCert.crt”) ??? It seems that it
works fine…
I’ve tested it on WinXP + SP2. Is there some betrayal ? Thanks for your
responses. Ondra