RE: Problem with xsl:number formatting

> So, in my mind, 'E' is a valid token on which to start.
> 
You're definitely in implementation-defined territory here. An
implementation may or may not support a numbering sequence that starts with
'E'; if it does so, it's implementation defined whether that sequence goes
(E, F, G, H, I) or (E, G, B, D, F). 

Saxon will allow format="E" and continue E, F, G, H, I, but there's
certainly nothing in the spec to require it.

I think the only reliable way to do this across implementations is to
compute the section number (either using xsl:number or an expression such as
count(preceding-sibling::x), add 4 to rebase it, and then format it using
<xsl:number value="x" format="A"/>.

Michael Kay
http://www.saxonica.com/