Sending SysEx to Blofeld Desktop


Trying to update the OS on my Waldorf Blofeld from Logic 9, but can't seem to set up the Blofeld so it is recognised as an external instrument. The Blofeld is normally connected via MIDI to an Axiom Pro 49, which is then connected via USB to my iMac; I record via the audio leads into my Saffire Pro 40 interface. For the update, I have also connected a USB cable from the Blofeld direct to the iMac. However, although I have set up (I think!) the Blofeld using the Audio MIDI Set-UP utility, the External Instrument plug-in does not show the Blofeld as an external MIDI instrument, and playing the MIDI update file does not affect the Blofeld at all. Does anyone have any thoughts on what I've done wrong here? Thx!

Setup: Duo Core Intel iMac, OSX10.7.5, Logic 9, Focusrite Saffire Pro 40 interface, Axiom Pro 49 controller.