Mine is the same way as mentioned in previous posts.  There is no outlet under the passenger seat and I believe that the ducting is separate from rad heat (defroster and under the dash).
I've never seen a van 85 and older that didn't have a gas heater in Canada.  I assumed it became an option for 86+ models.

My dad's 79 had the same venting from what i recall.  However my 73 Safari had heat coming out under the rear bench seat.  Not very helpful.
What i don't recall is how the switch works.  On my 85 it turns.  I don't believe you can use it to preheat the cabin.  I think it only works with the motor running (but i could be wrong - i know it sucks a lot of power so i wouldn't use it without the engine running.)  It will run indefinitely.  It keeps running for a minute after the van is turned off if you don't turn it off first.
I seem to recall that on my 73 (or maybe my 69 notchback, also with gas heater) the knob doesn't turn but is instead gets pulled and is more of a timer.  But my memory is lousy.  
When I used to drive my 73 around all my friends would hang out in the back, by the heater, and I would be stuck by myself in the front.  Bad friends but I understood.
And as mentioned before, they are awesome heaters.
Jeff in Winnipeg2009 Jetta wagon (for the kids)2007 New Beetle convertible (for me I mean my wife)1985 Westfalia GL (owned since 93)1969 Type III notchback (collecting snow)1979 Westfalia (dad's - long gone)1973 Type II Safari conversion (sold to a Minister - I am going straight to Hell I'm sure)
> Date: Mon, 9 Feb 2015 12:26:25 -0400
> From: RNicholl@NBNET.NB.CA
> Subject: Re: Eberspacher BA6 gas heaters on canadian waterboxer vanagons...
> To: vanagon@GERRY.VANAGON.COM
> 
> I cannot take pictures at the moment as the Hyena is in storage.
> 
> In my '88 Westy, the hot air from the Eberspacher enters the cabin in two places:
> 
> 1) In the cab there is a vent in the base of the driver's seat pedestal;   I cannot recall for certain if there is a vent at the base of the passenger seat, but I think not.   I also cannot recall if there is a hot air hose going to the centre console ahead of the shifter in my vanagon.   I'll have to drop the spare and crawl underneath in the spring.
> 
> 2) In the camper cabin, there is an aft facing vent along the raised edge where the front seat pedestals and ramp between the front seats meets the kitchen/cabin floor.  
> 
> 
> 
> On 09-Feb-2015, at 06:13, JordanVw@AOL.COM wrote:
> 
> > ok a few canadian listers  have said their waterboxer vanagons have
> > eberspacher BA6 belly pan gas heaters..  ive never seen or heard of this  before
> > but apparently they exist.    is there any canadian lister  with the BA6 on
> > their waterboxer van that can take pics of the ducting  setup?     where does
> > the heated air enter the  cabin?   on the waterboxer vanagons the center
> > duct hole in the dash  has coolant lines etc going thru it, this would be
> > where the heated air would  have come in for aircooled vanagons with the gas
> > heater.. so where does the  heated air enter the cabin?