chart in Report Builder 2.0 does not show all Category Fields in x-axis

I have a chart in Report Builder 2.0 with multiple series values (the fields added to the box along the top side of the chart) and no series fields (box on right side of chart) or category fields (box along bottom side of chart). The different values belong to different categories but there is no one field that splits these values between categories, so I cannot put a particular field in the category fields segment of the chart. However, in the Series Properties window for my chart, I can set the Category Field property to some arbitrary string. I was trying to set this Category Field property differently in my different series, but only the first Category Field value shows up along the x-axis in my chart. I have edited the Axis Properties to have an interval of 1, but I still only see the first Category Field. Beyond that, all my different values get clumped together on the x-axis with no space between them, and the first Category Field value is centered under all the bars, making it look as if they all have the same Category Field. How can I change this? See the screenshot below.

The red circled series values all have the same value set for their Category Field, while the other series values have different values set for Category Field. Despite the dummy chart showing separate categories A, B, C, etc., my actual char开发者_Go百科t when I render the report shows a single category: the value for the first series value's Category Field

Okay, it seems like Category Field doesn't understand anything but integers and dates. Instead of using string category names, I switched to using =0, =1, and so on for my different Category Field expressions. In the Properties for each value series, I set Data > DataPoint > AxisLabel to the string category name. Then my values are grouped according to their Category Field, and all the categories show up on the x-axis. It even obeys Category Field ordering when there are missing values: I had one value with Category Field 0 and another with Category Field 3, and it showed two empty tick marks on the x-axis for fields 1 and 2. The categories are also shown in order of Category Field, regardless it seems of the order the value series are arranged in the "Drop data fields here" tray on the chart.

One problem I noticed is that the chart spaces/sizes the bars as if every value series was showing up in every category. My chart is such that at most 4 bars show up per category, and I have a lot of categories, so it acts as if 4 * (# categories) bars are going to be stuck in each category. This makes my bars very narrow, and also causes them to space strangely.