Fenix 3 - Missing steps in daily activity

Hello,

I have a target of 10000 steps to achieve per day. I'm 100% sure that I saw a figure just above 10000 on my watch before going to sleep last friday. Both Garmin Connect and Fenix 3 are matching today (9734 steps). I just would like to know the procedure to modify the native FIT file (including the software to be used) in order to enter i.e 10100 steps. The reason for this is obviously the tracking of some badges !

Best regards.