unpad-brackets unpadding double brackets

I am using astyle for a different programming language called GSC, which uses double brackets to call a function variable:

func_var = ::func;
self [[func_var]]();

func()
{
	return;
}

The problem is:

self [[func_var]]();

is being changed to:

self[[func_var]]();

I want to use the unpad-brackets only for single brackets, can this be implemented?