Hi there, welcome to the site!!!!
Hope you are enjoying the van and it sounds like you are
Okay lets deal with this by internal and external connections....
External connection -
OK they would have given you a COAX cable as that is what needs to screw into there system. From reading your post it had the two screw type connectors on each end like this? -
This will not connect to your van as you have pointed out.
So you should have had on one end of the COAX an adaptor screwed into the COAX to make it a normal antenna plug like this (as you mentioned push rather than screw

) -
I am guessing some one has nicked the adaptor plug like the above and or they don't provide it.
I carry a couple of these in the van about 10 of them actually with a variety of connection types inlet and outlet.
So get one of the above adapters and next time they give you the coax cable, screw one end of the coax straight into there spot and then screw your adapter in the other end of the coax and plug this directly into your antenna plug on the right hand side of the van exterior next to the power point.
Just remember if you are using your adapter plug to make sure you take it out when you hand the coax back or you will end up like me and continually running out

!!!!!
Internal Connection -
Inside is just a reverse of the above, you buy a COAX cable for your desired length one end should just screw into the point in your van as you pointed out and in the other end you screw the correct adapter to plug it into your TV.
You can also buy antenna cord that don't require the adaptor like this, it just screws into the port in your van and then plugs straight into your telly. -
So once you have done this you turn of the booster (Green light should be off) on the external antenna plug in your van and you then just tune your TV in on auto tune.
It should automatically pick up the Austar / Foxtel channels when its tuned.
And that's it you are ready to go!!!
Most of these can be sourced from Big W, Kmart etc but I bought mine from a $2 shop in there electronics shop. People say it might be crappy quality but I have not experienced any major issues in using them.
I hope I have it right from your posts but that's how our vans our setup when we get the foxtel cable.
