Sweave problem on Mac OS when using umlauts and summary()

I have the following Sweave file which gets sweaved correctly.

<<>>=
m <- lm(y1 ~x1, anscombe)
summary(m)
@

I include the sweaved .tex file into another .tex file via include.
When I use a single umlaut in the .snw file a warning occurs.
As a result part of the summary output is not contained in the .tex file.

?
<<>>=
m <- lm(y1 ~x1, anscombe)
summary(m)
@

You can now run (pdf)latex on 'ch1.tex'
Warnmeldungen:
1: ?ch1.Snw? has unknown encoding: assuming Latin-1
2: ung?ltige Zeichenkette in Konvertierung der Ausgabe (wrong character in conversion of output)

Interestingly, this error does NOT occur, when I omit the summary(m) statement.

?
<<>>=
m <- lm(y1 ~x1, anscombe)
#summary(m)
@

You can now run (pdf)latex on 'ch1.tex'
Warnmeldung:
?ch1.Snw? has unknown encoding: assuming Latin-1

I know that I can prevent this by adding a line at the beginning of the .snw file:

\usepackage[utf8]{inputenc}

?
<<>>=
m <- lm(y1 ~x1, anscombe)
summary(m)
@

This gets sweaved correctly without warnings:

But this solution is not good as it is not the preamble of the .tex document where I add the usepackage line.
This will cause an error when processing the entire document with tex.

How can I achieve the last result in another way?
I tried:

Sweave('/Users/markheckmann/Desktop/test_sweave/ch1.Snw', encoding="UFT-8")

But this does not work either when the usepackage line is omitted.

I am stuck here. Can anyone help?

TIA
Mark


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Mark Heckmann
Blog: www.markheckmann.de
R-Blog: http://ryouready.wordpress.com











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