Tactix 7 pro - HR Zones - Based on "BPM" missing

Hi 

I would like to set my Heart Rate Zones using BPM instead of %Max HR but the menu Based on "BPM" is missing

I only have these options : %Max HR (=%FC maximale), %HRR (=%RFC), %LTHR (=%FC au seuil lactique) ... but not BPM

Does anyone have this issue on a Tactix 7 Pro ?