xml table reading problem

[Johannes Graumann <johannes_graumann@web.de>]

Hello,

Derived from the 'figure' and 'table' examples in the XML example document,
I came up with the following set of mapping rules for formating XML tables
with ConTeXt. 

\defineXMLenvironment 
  [table]
  {
    \bgroup
    \defineXMLpush[caption]
    \defineXMLpush[content]
  }
  {
    \placetable
      [\XMLpar{table}{location}{here}]
      [\XMLpar{table}{label}{unknown}]
      {\XMLpop{caption}}
      \ix
      \bTABLE
        \XMLpop{content}
      \eTABLE
      \x
    \egroup
  }
\defineXMLnested      [tr]    \bTR    \eTR
\defineXMLnested      [td]    \bTD    \eTD

When compiling a file with this rule set, I get the following error:

! Missing { inserted.
<to be read again>
                   \edef
\doifsomething #1->\edef
                         \!!stringa {#1}\ifx \!!stringa \empty
\expandafter ...

\switchtobodyfont [#1]->\doifsomething {#1}
                                            {\doifdefinedelse {\??ft
\normal...

\XML:ele:/table ...nown}] {\XMLpop {caption}} \ix
                                                  \bTABLE \XMLpop
{content} ...
l.437                   </table>

When switching to scroll mode, the tables come out ok, but I'm unable to use 

\defineXMLenvironmentsave
  [textref]
  [name=]
  {}
  {\in{\XMLflush{textref}}[\XMLop{name}]}

to refer to them ...

Any input would be highly appreciated.

On a side note: how do I, in a document with
general '\setupinterlinespace[line=2\bodyfontsize]' switch to 'small'
interlinespace for floatcaptions (and footnotes)?

Tried '\setupcaptions[style={small
\setupinterlinespace[small]},width=\textwidth]', but that doesn't work ...

Thanks, Joh