It will be better to have tunnel names for SSTP sessions like sstpX. The similar already used for L2TP and PPTP
ifname | username | ip | ip6 | ip6-dp | calling-sid | rate-limit | state | uptime | rx-bytes | tx-bytes --------+-----------+------------+-----+--------+---------------+------------+--------+----------+----------+---------- sstp0 | test_sstp | 100.64.2.0 | | | X.X.X.X | | active | 00:07:49 | 61.3 KiB | 713 B