garage door reveal

[heathldesign]

hey everyone,

i have not been able to figure out how to create the reveal for the way overhead garage doors are actually installed in north america. the outside face of the door slab is flush with the interior wall finish and the exterior casings are obviously on the exterior face of the wall with the siding (except for brick or stone veneer) i can get the door set back, but cannot get the casing in the correct location. has anyone figured this out?