I was wondering if anyone can help me out here?

Ive been using Cubase LE4 wth my M3, Radias R, Prophet 08 and SH201 going through MIDI interface with no problems.
I decided to disconnect my PC from the loop and connect midi out of the M3 into the Radias thru that and into the Prophet, thru that and into the SH 201 so I could just play around live.
The problem is, when I set the Radias clock to Ext. MIDI and the Prophet clock to MIDI out then set the SH201 clock to receive externally, non of the arps or mod sequencers work on anything other than the M3. As soon as I switch all the clocks back to internal, everything works again.
I've just reset all factory setting on all 4 synths and tried again, but its still the same!
Please can someone shed sum light, its driving me nuts!!
