Buying/selling bike between foreigners on foreign soil

[Gertmans]

Hi, I've been reading up a bit on paperwork and change of ownership. Most I read however is about selling the bike to a local. Now what I want to do is buy a bike from an Australian who left it in my house about a year ago. What I do not want to do is nationalize the bike to avoid cost and hassle. To make things slightly more complicated, I'm Dutch and I live in Bolivia. So I've come up with two solutions, assuming that legal change of ownership in Australia is impossible with me being in Bolivia and the current owner of the bike being in Sweden:
1 forge Australian papers
2 forge Dutch papers

In case 1 the current owner should send me the papers and I'm sure that, as I have time to do it, I can make a pretty decent 'copy' with my data on it. In this case I'd like to know how likely it is that custom officials here in South America will observe the odd fact that I'm dutch and I own an australian licensed bike. Any ideas?

In case 2 I think it might be wise to also get some Dutch license plates. No idea how to get those.... And someone to scan me some Dutch ownership papers? I've been out of Holland for some time, no idea what they consist of these days.

In any case I won't have the temporary import paper for the bike unless the owner still has them for Bolivia and they don't mention any owner. But I guess that's easily sorted telling the guys at the exit custom post that I was never given such paper.

But in worst of cases, will any suspicion arise from the fact that the other stamps in my passport will show nothing of previous travel (wich is the only way to get the bike to Bolivia as it's landlocked), neither will I be able to show any shipping documents (Netherlands - Bolivia) for the bike to get it to Latin America. I have no idea how this works.
Any of you guys ever been asked for such documents in case of doubt about the origin of the bike or am I fearing trouble in vain? I guess the smaller the border crossing the better right?

It may even be illegal to own a foreign bike as a foreign resident in Bolivia, but I guess that's OK as long as I don't tell anybody..... ;-)

Gert