This is further information to go along with Ray Semenoff's (VE6RHS) note on putting the IC-2700 into remote operation, either from the front panel of the rig or from a remote transceiver.
First you must put the rig in the REMO mode, push the DTMF button one or more times until REMO is flashing to the right of the left side channel display.
I played with this and followed the sequence given in the manual on page 63 to enter commands remotely and that to turn the XBand rpt on, you need only put 'D' in the command part of the sequence. To turn the XBand rpt off, need only to omit the command part of the sequence altogether.
i.e. - for XBand Rpt on B000# D B*
for XBand Rpt OFF B000# B*
Also, to enable the XBand remote from the front panel of the rig, press and hold the SET button, then immediately press and HOLD the DUP button, and then press and HOLD both of the channel buttons until the flashing L appears on both sides of the display.