CAML NOT CONTAINS?

I can't find documentation on this so I think it doesn't exist?

It is a very common occurance that you'd want to select where column NOT LIKE %O_V

I want to only get those items where the name DOES NOT end in O_V

I found this but do not know how to negate it.

Thanks.

<Contains>
  <FieldRef Name = "Field_Name"/>
  <Value Type = "Field_Type"/>
  <XML />
</Contains>

Tom