How about a little about you and your company?
Yes, thankyou for asking. This is a more lengthy introduction.
I have been making games ever since I was 11. This started out on MSX, Sinclair, C64, Amiga and onwards to more modern platforms.
My first job was as a programmer in the game industry, but I have since then spent most of my time in marketing. I started an agency in 1999 that I sold in 2006. During that time I made numerous casual games for companies like Saab, Ericsson and Nokia. All along I have been developing games in my sparetime.
I now run a communication agency that does everything related to marketing
i can do that. but you'd have to wait until hhexen is finished which is scheduled for "when DNF is done" 
Ok, what I'm asking for is pretty basic, so I figure someone might have the bulk of this in an existing project. There is nothing better than getting paid twice or for work already done. 
Well, if you won't tell them neither will we, how about that?
Seriously, it must be a VERY strict contract if it disallows you from doing any other work for another company it all. Usually, if you have such a clause in your contract at all, it's limited to your own field. (so that'd be if you work for another game developer).
Even then, there's no legal way for them to find out you're doing that work (short of you announcing it on the forums here).
Why require an invoice from a company though? An individual should work just as well , as long as they bill you properly… the individual is then responsble for paying any taxes. Or is there some obscure swedish law for non-EU persons against this?
Swedish tax laws are radically different than the US.
The state I live in allows a employer company rights to ANY commercial project that an employee has worked on during the employment period, unless it is pre-approved and authorized in writing. This means that any commercial project I work on and don't tell my employer about is eligible for a lawsuit. The scope of the project has little bearing, strange I know but this is not the only state with laws like this.
Ok, that is truly odd. I never heard of such a thing…
I know there have been disputes about ownership of work created for an employer during worktime, in many countries (usually in the end the employer actually wins, most famously the inventor of the blue LED, in Japan). Never before heard of a company owning what you do in your own time. America, truly a strange place at times.
Those are the contracts you never sign…I've had a few of those contracts put in front of me. After I stopped laughing I explained that I wouldn't sign such a contract. Generally speaking they'll never mention it again and go on or they'll revise it to make it less insane.
I asked my auditor about the invoice, and found that the laws in Sweden are very strict regarding this.
However, if this is the only barrier then please drop me a message. We might be able to come up with some alternatives.
So far I have some offers, but unfortunately none have good skills with jMonkeyEngine. If this proves true by 11th of March I may have to revert to plan B and code this myself. It’s not optimal, because I’m already coding server and editor.
In that case I would like to cut some corners by paying someone by the hour to give me speedy e-mail support. Basically give me guidance, tips, helping to review my code and discuss the pros and cons of various implementations.
So, if you are interested to help in any way please e-mail me.
You should cross-post this to off-topic, I think not everyone reads Dev general.
Also as mention: http://www.rpgtoolset.net/ is a pretty nice tile based engine. Probably would need some work to match your exact requirments but who knows…
Thanks for the tip.
Ok, 3 more days until the application window closes.