Getting a UK registered transit van through TÜV

I have a UK registered Transit van here in Germany (2,5 Diesel).
I took my Transit van to the TÜV the other day, He says I need a special number before I can proceed. ( nothing to do with the Log book) but am not sure what he means.
Is it to do with it being insured as a LKV or a PKV ? .
Someone told me there is a big difference costwize to do with insurance due to the weight it can possibly carry ( PKV / LKV).
I only use my van for commuting at the moment.

Can anyone help?

I've put a UK registered car and motorbike through the TUV and think they have given you duff advice.

The bike was no problem, they didn't even realise that the headlight needed changing for dip to the right but with the car they started to say that I needed to register it in Germany first.
Because I had already done the bike, I realised that this was crap, in fact you can't register a car without first getting the TUV, so I argued the point and they did the TUV.

The most expensive bit was the headlights.

I have a motorbike too but that didn´t seem to pose a problem.

Maybe I need to go back and ask again.

Apparently my van would be cheaper for insurance under LKV insurance so I am assuming they need a number because of this.

sorry wrong post !!!

New update

Having to reply to my own post. This "certificate of conformity" is to do with safety, I.E. are the seat belts in the vehicle of the three mount type system as depicted by the European system of safety factors safe enough as depicted by the system of European system of safety factors. So I say to a small type Hitler man in charge of the "TUV" about my FORD TRANSIT VAN made in the "EU" can I have an MOT please. Yes but you need a Certificate of conformity, oh I see this is because i am importing a vehicle from out side of the European Community like Peru which means I need a certificate??? TO BE CONTINUED !!!