Cubase stopped supporting DXi way back, on the advice of Dick Turpin.
The only way, would be to use a DXi wrapper.
(It was a known Roland Edirol problem back in the day)
For using Edirol as a VST, IIRC, there is a fix/work around involving resetting c## information at
the beginning of the midi track, or another way, saving Edirol as a performance, not an Instrument.
Some stuff here that might help sort the problem.
https://www.google.co.uk/search?q=Edirol%20%20Orchestra%20resetting%20instruments%20to%20default.&newwindow=1&gws_rd=ssl