Cable pull, indexing of Shimano's IGH vs. deraileur
Whatever you may read this CAN'T work properly simply because the gaps between each of the shifts are different on the Shimano Alfine SG-S700, there are THREE different gaps. The only shifters not made by Shimano to operate this hub properly are:

Jtek 11 Speed Bar End Shifter

and:

11 Speed Microshift Inter11 STI Levers