[Elecraft] ATU and Bandpass Filter

[Lane]

A question about the K2. Taking it to the club for FD and I have a
bandpass filter (CF-20) which says "Never use radio's internal tuner
with filter."

I have the internal ATU installed. Is there a way to bypass that? Or
should I just use the "main antenna" jack (manual says never use if
ATU installed) on the bottom left, instead of the two midway in the
middle?