XS748T as a static gateway/router? Inter VLAN routing?

We have an XS748T and have recently signed on for a new Internet service with a /29 address range. It has been my past experience most of the time that an ISP will just hand you your /29, reserve one IP for their router and have you use that as your gateway. This is not the case this time.

Our new ISP has handed us our /29 AND a /30 WAN address range and we are to handle routing. We were not ready for this. This service is also a 2G service which is why this 10G switch is necessary to use. The connection is also fiber which we have a working SFP+ device on port 47. Port 47 is in its own VLAN.

Is it possible to have the switch itself perform interVLAN routing? For example:
Our Internet PTP WAN address will be 100.0.0.2/30, directly plugged into xg47, assigned to VLAN 20
Our subnet is say 100.111.0.0/29 (100.111.0.1 - 100.111.0.6) on VLAN 30 with various switch port assigned.

There is a section on the switch's UI that is for routing and suggests that inter basic VLAN routing can be done on this device. How would I get VLAN 30 to use VLAN 20 as it's gateway? I know I can add a default route for 10.0.0.1 for VLAN 20. How would I get VLAN 30 to point to VLAN 20 on this device?

Edit: Not sure this can be done. Under normal conditions you have to route subnets via IP addresses. Since there's no way to assign direct ports IP addresses on this switch it doesn't appear that this will work. Am I wrong?