Using the full width of an Excel chart with two Y-axes

I am trying to create a line chart in Excel 2007 with two data series, each
with their own Y-axis.

First, I create a simple chart by selecting the two data series, and
choosing [Insert Charts Line] from the Ribbon. I now see the following
chart in my workbook: http://i41.tinypic.com/343jfdk.png

I then continue my quest by right clicking one of the data series (lines)
and choosing [Format data series Series Options Secondary Axis]. My chart
is now looks like this: http://i40.tinypic.com/8wy3wg.png

This is almost what I want. I did not expect to see the gap between the last
X-axis tick point (x = 5) and the secondary (right most) Y-axis. Why does
Excel introduce this gap?

Is there anything I can do to avoid it? I have tried right clicking the
X-axis and seleting [Format Axis Axis Options Position Axis: Between tick
marks], but that only introduces a similar gap on by the primary (left most)
Y-axis.

The following data is sufficient for me to reproduce the problem. Paste it
into Excel, select the block of numbers and create a line chart. It will not
draw the exact same lines as above, but it will illustrate the problem with
the right side "padding".

1 2 4 8 16
100 210 440 900 2000

I hope someone is able to help. Thanks in advance!

/Jørn Schou-Rode