custom wifi hotspot voucher template in sophos cental possible?

Hello all,

A customer needs outdoor access points (APX 320 X).
Among other things, a hotspot with vouchers is needed.
Until now (without the outdoor APs) the vouchers were managed with a customer specific template in the firewall. However, this is not possible with the outdoor APs, as they have to be managed via the cloud.
Now I've been searching for some time in Sophos Central (and the associated documentation) for the possibility of adapting the voucher template to the previous layout.
But I can't find anything.

Is this possible at all, and where can I find it?

Many thanks and best regards
Mike