I believe OMIT is used to remove a complete field from the data model for that user, not single values from the field.
But you can state the FIELDNAME instead of the OMIT, and then definde the values to reduce the field to for each user, doing this repeatingly or using star symbol * if you want more than one value available for one user.
Note sure if you know the document explaining section access:
Ah, and take care of the UPPERCASE names using section access.
Hope this helps,
To enable the OMIT in your Section Access, you should check/do this.
On your QlikView desktop application, go
Settings ---- Document Properties---- Opening,
check the box of "Initial Data Reduction Based on Section Access"
Note: OMIT option is to omit the whole Field, not a single value of that field.