xtable with \begin{tabular} and only.contents

I have found that I like having my captions and labels in my latex document
rather than having them contained in my xtable output file (I haven't fully
gone to sweave yet).

  I know I can do something like this by using the
'only.contents' argument in xtable.  Unfortunately, the only.contents
argument also removes the \begin{tabular}{rrrrrr}&  \end{tabular} (in the
example below) of the table.    This means that I have to go look up each
table to determine the number of columns.

Is there a more automated way that I am missing? i.e only.contents but with
tabular headers (but not \begin{table})?
Thank you.

CODE:

## Demonstrate include.rownames, include.colnames,
## only.contents and add.to.row arguments
set.seed(2345)
res<- matrix(sample(0:9, size=6*9, replace=TRUE), ncol=6, nrow=9)
xres<- xtable(res)
digits(xres)<- rep(0, 7)
addtorow<- list()
addtorow$pos<- list()
addtorow$pos[[1]]<- c(0, 2)
addtorow$pos[[2]]<- 4
addtorow$command<- c('\vspace{2mm} \n', '\vspace{10mm} \n')
print(xres, add.to.row=addtorow, include.rownames=FALSE,
include.colnames=TRUE, only.contents=TRUE, hline.after=c(0, 0, 9, 9))


Output (only.contents=TRUE)
% latex table generated in R 2.13.2 by xtable 1.6-0 package
% Fri Oct 28 11:38:10 2011
1&  2&  3&  4&  5&  6 \\
   space{2mm}
  \hline
\hline
1&  7&  6&  6&  5&  9 \\
   1&  1&  1&  5&  7&  7 \\
    space{2mm}
7&  3&  9&  8&  0&  5 \\
   0&  0&  4&  1&  5&  2 \\
    space{10mm}
4&  1&  8&  5&  7&  1 \\
   2&  4&  5&  9&  5&  4 \\
   6&  3&  3&  5&  5&  8 \\
   7&  6&  1&  0&  7&  6 \\
   4&  4&  8&  8&  3&  2 \\
    \hline
\hline

Output (only.contents=FALSE)

% latex table generated in R 2.13.2 by xtable 1.6-0 package
% Fri Oct 28 11:39:23 2011
\begin{table}[ht]
\begin{center}
\begin{tabular}{rrrrrr}
  1&  2&  3&  4&  5&  6 \\
   space{2mm}
  \hline
\hline
1&  7&  6&  6&  5&  9 \\
   1&  1&  1&  5&  7&  7 \\
    space{2mm}
7&  3&  9&  8&  0&  5 \\
   0&  0&  4&  1&  5&  2 \\
    space{10mm}
4&  1&  8&  5&  7&  1 \\
   2&  4&  5&  9&  5&  4 \\
   6&  3&  3&  5&  5&  8 \\
   7&  6&  1&  0&  7&  6 \\
   4&  4&  8&  8&  3&  2 \\
    \hline
\hline
\end{tabular}
\end{center}
\end{table}

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