I don't follow what you are saying here at all.   How can you, or BMC, be
graphing anything other than a numeric value?
A Display String is a textual convention for a particular kind of octet
string, in this case printable ASCII characters.
It is sent by an agent as data type x'04', which is the BER encoding for an
octet string.  All SNMP data is preceded by its data type and length so
that the receiver knows precisely what it is getting.

Now the only thing you can collect and graph in NetView are numeric values:
integers,  counters, gauge values.  Things that vary numerically over time.
That's all.

So are you saying that this BMC patrol MIB is incorrect and that what they
are calling a Display String is really something else, a numeric value of
some kind?  Then you would have to change the MIB and reload it just to
even try to get us to collect on it.  You said you weren't sure that even
makes sense.  Well, as far as I can see, that's the only thing that does,
since you cannot graph a string of printable ASCII characters as a rate of
change.

But this would be a workaround only if the MIB really is in error and the
Patrol agent is really sending some kind of numeric data, encoded as x'02'
integer, or x'41' counter, or x'42' gauge.  If it is really sending  type
x'04' octet string, then it is highly likely that the MIB collector isn't
going to know what to do with that kind of data, and will just  error out.
I don't know that for a fact, so you are welcome to try this if you like,
but I am sorely puzzled by your description of the issue here.

James Shanks
Level 3 Support  for Tivoli NetView for UNIX and Windows
Tivoli Software / IBM Software Group