Bc2000 (for the BCF2000 & BCR2000)

Hi,

I'm getting my bcr-2000 in the next couple of days, mainly so I can
have hands on control of my Roland MKS-50 (rackmount Juno).

I'm having a bit of trouble visualising all the midi connections, and
think I may need another midi splitter device for it all to work.

I have (or will have) :

MKS-50 (IN OUT THRU)
BCR-2000 (IN OUT THRU/OUT)
Keyboard (OUT)
Presonus Firestudio Comp Interface (IN OUT)

I'd like to be able to tweak the MKS-50 via the BCR-2000 while playing
on my keyboard.  

Can this work? :
Keyboard OUT-> BCR2000 IN
BCR2000 THRU/OUT -> Firestudio IN (does this include the input passed
to it as well as the actual output of the BCR tweaks?)
Firestudio OUT -> MKS-50 IN (using midi-yoke or something to do the
routing)

It seems like the problem will be with the bcr2000 thru/out.   Will I
need a device that takes two inputs (bcr and keyboard) and spits out
one output that I can feed directly to the mks-50?