Management Mkt R11e-LTE when it's MODEM (ip passthrough)

Hi,
My questions is the followings:

I have an Mkt R11e-LTE in MODEM mode (ip passthrough). The public IP of the LTE is redirected to the MTK RB, as described in the drawing.
Since the MKT R11e-LTE is in MODEM mode, I lose its management.

------ MKT R11eLTE (ip passthrough)
|
|
------ MKT RB (Public IP LTE)

How can I have management??

grateful!

There have been multiple posts on this in the past month. Just search.
You can either setup a VLAN or use Romon.