Hello Francois,
no problem, you're welcome!
Since it seems to be pretty complicated to find a suitable aftermarket filter for the 1.3 Sirion, you're probably better off with a generic one, yeah.
It would be interesting though to know which filters (also for other models like the Myvi) fit and which don't... so if you one day find a fitting aftermarket filter, please drop us a line about it - quite a lot of people in here might be interested to know!
Best regards