How to replicate short selling

Best way to replicate short selling? The platform gives you an error message if you use negative quantities for the stocks, so my method is to simulate short selling as a stock being delivered to me and then sold immediately by me for cash. When I want to close the position I buy it back then send an outward delivery. The only problem is that PP does not consider this to have been a trade. Any suggestions? How do people here replicate short selling?

Just sell it (resulting in a negative number of stocks), then buy it back.

Yes, short selling is not fully supported, but that only affects performance calculations, trades etc.

Hi! In what way does it affect performance calculations?

Thks !