You might find this of interest
Legalisation of a trailer purchased in the country of the EU (as of January 2011)
A recently acquired our partner in tow in Spain and it is this process that we describe briefly, and with some comments, as usual.
1) The trailer is suitable for a vessel up to 5 meters with a gross weight (PB) of 450kg, and Tara's own trailer of 110Kg (empty weight of the trailer - which means you can load up to 340kg in weight) ;
2) The first question to be considered has to do with PB: more than 300Kg, which requires it to have Registration / Booklet / Property Register. Although the weight of the vessel that will carry is of 110Kg, and with it the set will 220kg and 300Kg even, the fact is that the PB is 450kg, and the authorities would not regret for one to apply any sanction - enough to look to its data plate.
3) Addressing the IMTT, the applicant is requested IMTT Model 9 form (available online), the original log book (which in Spain is also a sort of "roadworthiness test" described in detail) and the purchase invoice on behalf of applicant. Then arose the question of the EC type-approval of the trailer, but in Portugal - Spain since the booklet is demonstrated there. The process was delivered, but with a request asking that the IMTT deign to give that approval after verifying that the fact that model is not already approved in Portugal, but has an EC type-approval in another EU country. Note: There seems to trailers built under license in Portugal and Spanish design. So IMTT certify that the trailer corresponds to a vehicle that can travel on the road;
4) After some time, the technical advice given is positive, eliminating a further inspection in center IPO because it was a new trailer;
5) It is a booklet issued provisionally, as indicating the permanent registration;
6) Final step: Motor Registry to register the property joining the Unified Model (available on the Internet) the document issued by IMTT (carnet "provisional"). It returned a receipt along with the booklet "temporary" was used to purchase the registration plate, and on the road, after effecting their Insurance.
7) costs € 165 in IMTT (if the trailer was already approved would be € 33), € 50 in the CRA; Half a dozen lost hours at both locations, and some typical pitfalls that do not comment ...

)