If you have high unburned HC, one "workaround" is to add a bottle of HEET into a half full fuel tank.

Drive 80-100 miles, running the heck out of it on the freeway etc.

Then try smogging again, perhaps at a different smog shop....maybe your smog shop needs calibration?  Or try a Vanagon friendly smog shop like 7 days smog in Berkeley.
http://www.yelp.com/biz/7-days-a-week-smog-check---test-only-berkeley-5

Heet is an alcohol so it does not burn/unburn as a hydrocarbon....the kids with Japanese tuner cars swear by it for passing smog tests.

HEET in the yellow bottle is about $2 at FLAPS/Walmart etc.
http://www.goldeagle.com/brands/heet/default.aspx