MIDI LOOPBACK for SCALA in SONAR 8

Hello,
I wish to use oriental scales with SONAR 8, by loading scl files made with SCALA.
It is OK with DIMENSION PRO, but with other VST, like Vienna or EWQL Play, I need to insert something between the MIDI track and the instrument track.
SCALA is not recognised in SONAR.
MIDI YOKE is recommended, but I do not understand how it works.
In short I need virtual midi cables to connect :
midi data > SCALA > vst instrument
Thank you.