back quote as an operator

Hello,
I've just tried installing version 7 and have hit a problem because
of the new meaning of back quotes to mean a list of character codes.
I have a module who's sole purpose is to export some operators, including
back quote as a unary operator, like this:

module(ops, [
	% …..
	,	op(150,yfx,`)
	% ….
	]).

I've worked how out to put
	:- set_prolog_flag( back_quotes, symbol_char).

in my .plrc, and so loading module ops from the top level works fine.
However, if I try to use module ops from within some other module,
I get the error "string to long" because SWIPL goes back to interpreting
back quotes as a string delimiter.

How can I get back to the old behaviour?

thanks,
Samer.

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