I think you may try cutting the control wire from AVCR to the boost control solenoid and connect white wire to AVCR / brown wire to solenoid - this will keep the solenoid always open when HFS-3 is in failsafe mode, irrespective of AVCR mode/settings. Your boost will be then determined by the breakdown pressure of the spring in you wastegate / wastegate actuator.
You may have a look at the diagram Richard posted when I was asking re. failsafe operation, makes it all much easier to understand
http://www.aquamist.co.uk/vbulletin/...90&postcount=6
PS. hope it helps just while Richard is not in the office - hopefully Richard will post when he's back as I didn't have any experience in wiring hfs-3 + avcr myself...