Hi Gerasimos
Going through previous cases, we can identify a couple of cases mentioning utilizing PX to set these attributes with rule string values.
While we do not have an example to share at this stage, you might want to try different date formats to see which one is accepted (ie yyyyMMdd, yyyy-MM-dd etc)
Appreciate if you could share your feedback with any progress made.
If you still require help, you might want to raise an official Support ticket.
Regards
Rinat