So I've written <ENTITY InvisibleTimes "&#E89E;">, but XT tells me
"character not allowed"

I think the only problem is the missing "!" in the declaration; should be:
     <!ENTITY InvisibleTimes "&#E89E;">
      ^

=============================================================
John E. Simpson
simpson@xxxxxxxxxxx
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I put contact lenses in my dog's eyes. They had little
pictures of cats on them. Then I took one out and he ran
around in circles.  (Stephen Wright)