"°" not accepted under MacOSX

I am developping a package (pgirmess) that since long does not go through 
CRAN MacOSX checks, just because I have this command in one of the examples.

text(mydata[,3],mydata[,4],paste(round(dirs,0),"?"),cex=0.7)

It makes:

<ERROR: re-encoding failure from encoding 'latin1'>
text(mydata[,3],mydata[,4],paste(round(dirs,0),"+
+
+
+ cleanEx()
+ nameEx("distNode")
Error: unexpected symbol in:
"cleanEx()
nameEx("distNode"
Execution halted

The description file (following some earlier recommandation) includes:
Encoding: latin1

Is there any way to make "?" accepted by MacOSX checks ?

Cheers,

Patrick

The subject line is untrue.

We recommend in 'Writing R Extensions' that you encode such characters 
as \uxxxx sequences, in this case "\u00b0".  However, this is more 
likely to be a locale problem on the check server, as pgirmess checks 
out on my Mac.  In fact, the top of the log is

# using R version 2.11.0 beta (2010-04-12 r51689)
# using session charset: ASCII
# checking for file 'pgirmess/DESCRIPTION' ... OK
# this is package 'pgirmess' version '1.4.4'
# package encoding: latin1

and you cannot reencode latin1 to ASCII ....

I don't know why you would choose to use something that makes your 
package fail on many Japanese or Greek or Russian systems, and of 
course in C locales.  Plotmath is portable, and these days "\u00b0" is 
also pretty portable.