Support about USIM applet installation on sysmoUSIM-SJS1

Hi, I was trying to install a custom applet on sysmoUSIM-SJS1 SIM cards. Following the guide present here https://osmocom.org/projects/sim-toolkit/wiki and using shadysim I was not able to do that ( it gives me an error related to the fact it doesn't receive any status word back after sending an APDU, I think it's a bug but we can discuss about that later). I ended up using Global Platform Pro to install it but it only loads the applet on the card as a module of another package and doesn't make it selectable. I also tried to upload the applet suggested by you in the guide, but I got same result. Is it something related to the sim card? Should I buy the SJA2 version? Can you help me?

Thanks, Matteo