Text or tags choice with XSD

Hi,

Here are two <time> elements differing only in there content :

1) 
<doc>
  <time>14:09<time>
</doc>

2)
<doc>
  <time><hour>14</hour><min>09</min></time>
</doc>

In an XSD schema, how to indicate that the <time> element can contain text
and only text or <hour> tag followed by <min> tag?

I tried with a choice group containing two <time> elements with different
types but it doesn't work : it is not possible to have two elements with the
same name.


Thanks.
Pierre.