Crosstab queries, and null values

Hi everyone,

I have a crosstab query attached to a graph on a report. It shows
quantity of widgets produced by each employee for a specified period.
The client wants all months shown regardless of zero widgets. If I
just use the Access graph wizard, it only shows the months when there
are some values not all months with or without zero values.

The final graph is supposed to be sum(widgets) and each bar represents
a worker.

So...

MonthSt WorkerName #Widgets
01/Jan/2010 Bob 10
01/Jan/2010 Dave 5

01/feb/2010 [null] 0


01/Mar/2010 Bob 16

01/Apr/2010 [null] 0

01/Jul/2010 Bob 1
01/Jul/2010 Dave 7

etc

Creating the crosstab based on the above data via the wizard is Ok,
but where the workername is
null, it displays "" on the crosstab query and consequently with its
own coloured box on the legend even
tho' there is no data for it and the bar is not shown on the graph.

Can I remove it? Or mask it or just suppress those values?

Thanks in advance

Edwinah63