Criminal Code Warning: this is not an official translation. Under all circumstances the original text in Dutch language of the Criminal Code (Wetboek van Strafrecht) prevails

7.  A conviction as referred to in subsection (1)(2°) shall also mean an irrevocable conviction for 
similar offences rendered by a criminal court in another member state of the European Union. 
Section 38n 
1.  The measure shall be in force for the maximum period of two years, counting from the day on 
which the judgment by which it was imposed becomes final. 
2.  In the determination of the term of the measure, the court may take into account the period of time 
the convicted offender has spent in police custody, pre-trial detention, in a psychiatric hospital or 
an institution intended for clinical observation under an observation order prior to enforcement of 
the judgment.