Poipet-aranya Ticket Out Requirements

I did do a search on this one but have found no recent information.

Here is the thing. I am presently in Phnom Penh and hope to overland to Battambang to see a friend. From there I was hoping to cross over to Thailand at the Poipet-Aranya border and from there bus it to Nong Khai and cross over into Laos. With those travel plans there seems to be no way I can even consider buying an airline ticket being I would either need to backtrack to Phnom Penh to fly or head down to Bangkok to fly to Vientiane. I was hoping not to do either.

Does anyone have any tips for me in regards to supplying an onward airline ticket at the border? What are other people doing? Are slightly bogus bus tickets availabe in Poipet which show a return to Cambodia from Thailand?

Now I have no plans to scam the Thai immigration but seem to be in a odd situation of really having no airline flights to schedule. Geography is playing an intersting role in my case. Thanks in advance for any information you may have.