[suicideneil]

Of the 6000 odd members, only a few dozen are regular posters, so....

There is a very simple trick you can perform; charge the lipo as a 4s pack until the voltage of each cell is at the nominal level or just over- thats 3.6v each, so the total voltage will be 18v. Now, stop the charge and restart it- the charger should recognize that you have a 5 cell pack and ask you to confirm this before it starts the charge.

Im assuming when you connect it up and select 5s lipo, it only reads the pack as a 4s item? Thats due to the voltage of the pack being lower than the nominal/ resting voltage of a pack that size; the cells are discharged to ~3.0v per cell, but the charger is looking for 3.6v (or 18v vs ~15v, however you want to look at it), so it thinks you have a smaller voltage pack connected up.

Its a fairly common issue, I get the same thing with my Bantam BC6 charger, so I just use that trick and it works every time. You can also charge the pack as a nimh pack at 1c until the voltage hits the needed level, then change it to the correct lipo setting and finish the charge.