The bridge, aka ME-RVC, also has to support Lithium and the inverter does as well. So even if the Vegatouch will accept a Lithium setting, it will have no effect if the other pieces aren't "L" versions.
talks about the various Magnum inverter "levels", but as far as I could see there is no discussion of Lithium compatibility there.
The ME-RVC, ME-RC and ME-ARC now also come in an L version, but again if the inverter is not also an L version those settings will not work.
According to this page
L support was added to key Magnum products in July 2020.
provides some additional detail.
You should check if your inverter has an L at the end of the part number if you expect to use the LFP setting in your new remote.