typesetting chapter--label for cross references

[Guy Worthington <guyw@multiline.com.au>]

I'd like to display a cross reference, using a en-dash to separate the
chapter number from the text being cross referenced.  In the example
below, if you look at label attached to the example caption "A Sample
XML file," you'll see that it is typeset as

    Example~1--1

however if you look at the cross reference to the example, it is
typeset as

   Example~1.1

how do I change the period (.) separator in the cross reference to an
en-dash separator (--).

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\defineenumeration
 [example]
 [location=serried,
  text=Example,
  before=\blank,
  after=\blank,
  way=bychapter,
  style=italic,
  separator=--]

\starttext

\chapter{One}

\in{Example}[ex:Simple-doc] has the chapter number separated from the 
example number by a period, and not an en-dash.

\example[ex:Simple-doc] A Sample XML file

\startXML
<?xml version="1.0"?>
<?xml-stylesheet href="simple-doc.xsl" type="text/xsl"?>
\stopXML

\stoptext

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