(1)    Upon application and payment of a fee of $50, the department shall register a semitrailer which is operated in connection with a truck tractor or hauled by a motor vehicle and used with a device which converts the semitrailer to a trailer. Registration under this section is valid without the payment of any additional fee while the registrant is the owner of the semitrailer and, with respect to the sale of a leased semitrailer to the lessee of the semitrailer, while the former lessee is the owner of the semitrailer if the lessee reimbursed the lessor of the semitrailer at the time of registration of the semitrailer for payment of the registration fee under this subsection. The department shall issue a permanent semitrailer registration plate to evidence registration under this subsection.

   (2)   

      (a)    Upon the sale of a semitrailer registered under this section, the seller shall remove the registration plate and destroy it. The purchaser shall immediately apply for registration and pay the full applicable fee prescribed in sub. (1). This paragraph does not apply to the sale of a leased semitrailer to a lessee eligible to maintain permanent registration of the semitrailer under sub. (1).

      (b)    The seller of any semitrailer registered under this section shall receive no credit toward the registration of any other vehicle.