[R] plots to metafile and x/y ratio

[juli g. pausas]

Dear all,
I have a problem which I'm not sure if it is due to my machine or if I'm 
doing something wrong.

I'm ploting a little map using  plot(val, type="l", asp=1)  where val is 
the object with the latitude/longitude data.
In the screen the figure is perfect, and I can copy to the clipboard and 
paste it to other places. I can also saved using png() or jpeg(), 
althoug the quality is much lower. However when I try to save it as 
metafile (from the plot window or by using win.matafile), the file I 
obtain do not keep the x/y ratio. I'm interested in this metafile 
because the quality in much higher then the png, jpeg.  Any suggestion?

I'm working with R.1.6.1. on Windows.
If somebody is interested, I could send them the files, they are very 
small (45 KB).
Thanks in advance.

Juli