How to get a rule to fail on blank responsibilities?

[Michael Pokraka]

G'day all, 
Passing a blank value to a responsibility will always result in a positive
test. Can't get them to fail on blank data. Unless of course I'm having a daft
day (quite possible, it's been a long one!)? 

Now, the tricky bit is that I have many values to test against, but lets keep
it simple: 

Resp1  Plant = 1000, DocType = *,  Agent 1
Resp2  Plant = *,    DocType = ZZ, Agent 2

If I test this without entering any data, it will return all agents, even with
'Terminate if no resolution' switched on. It somehow feels like a stupid
question... but how to get around that? 

In short I want only those with MATCHING data to return agents. I.e. in the
example above, it I test it with Plant 9999, it will return Agent 2 (since the
doctype is blank). For my purposes, this should also fail (but isn't as
important as both blanks above). 

Any obvious answer I might have missed? 
Cheers
Mike