If I put my modules in the top positions (like top1, top2...), then the suffix formating appear normally, but when the module is moved back to the banner1 or banner2 position then nothing happens. See the screenshot for the module tunings.
I agree with you when you say that the suffix does not appear in firebug. That's why I mentioned earlier that something prevents the suffix to act on these modules positions (banner and header). They must be like the footers position where no formating normally occur, and I was wondering how to enable the suffixes on these positions.
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