I'm sorting a series of chapters based upon the chapter number. The numbering system is decimal:

3.9.1
3.9.2
3.9.3

and so on.

My problem is that when the base of one portion of the decimal rolls over, for example, when it goes:

3.9.9
3.9.10
3.9.11

The last two chapters are being sorted prior to 3.9.2.

I'm currently casting the sort key value to xsd:decimal

<xsl:sort select="xsd:decimal(@number)"  />

but it's not producing the desired sort order. What am I missing?

Thanks,

Don