changing or disabeling Kenwood TM-V71A time out timer

[KD4UPL]

I'm looking for a replacement for my 18 year old Icom IC2340H. I want cross band repeat capability and DTMF remote control; the TM-V71A meets these requirements. However, when in cross-band repeat mode it has a 3 minute time out timer. Kenwood tech support says it can not be disabled or lengthened. This is an unacceptably short time frame. When operating into a repeater with a net going on many operators are too quick on the trigger and don't let the squelch tail drop for over 3 minutes. This kicks the mobile radio out of transmit until someone finally lets the repeater drop.
My Icom will transmit as long as it receives a signal. Has anyone tried to or succeeded in disabling or extending the time out timer on this radio?

[WB6DGN]

Sounds as though its done in firmware.  Short of going in and hacking that firmware, if that can even be done, you're not going to be able to change it.  They probably set that fixed value to allow the radio time to cool off between transmissions.  Those little mobile radios generally have a very short transmit duty cycle and this is their way of helping to protect it from overheating.
Tom