Searching to match reminder (Begin) Dates

[danson]

I have:

Search where:

Begin date, less than or equal to (date 1 week from now)
and
Begin date, greater than or equal to (today)
and
Begin date, exists


However this also matches items with Begin date present but completely blank.

How can I get the search to not match these fields? Basically I need some sort of 'not null' match.

I've tried adding:
and
Begin date, not equal to, [blank]

but that does not work either.

Thanks!
Dan