If you work as a temporary employee, you build up just as much pension as an employee with a permanent contract. Your pension is calculated on the basis of the income you build up over the course of your career, so that includes your income as a temporary worker.
For the supplementary pension for permanent employees, a certain percentage is deducted for the sector pension fund. However, this supplementary pension is only possible at a company where this supplementary pension exists. Your percentage as a temporary employee is not sent to this fund. You do receive a pension bonus that is equal to the pension contribution that the employer pays for permanent employees. This amount will be mentioned separately on your pay check and will be paid by your temp agency.
So, to cut a difficult explanation short: yes, you build up your pension when you work as a temp; and yes, in certain sectors an additional pension will be paid, but by your temp agency.