Buffer not accounting for latitude

[GoogleCodeExporter]

I'm attempting to draw a buffer around a line or polygon and arcgislink seems 
to return an area of constant visual thickness instead of an area of constant 
geodetic thickness. See this example to see what I mean:

http://jsfiddle.net/dtjohnst/mk9Eh/embedded/result/

In this case, I drew 4 circles with a 150 nautical mile radius at (80N,80W), 
(60N,80W), (30N,80W) and (00N,80W). I then draw a polyline from (80N,80W) to 
(00N,80W) and finally a buffer of 150NM around that line. Given the mercator 
projection tends to squish things together around the equator and widen them 
out near the poles, the circles seem correct (and they appear to be if you zoom 
in and check the geographic references), hence why the northernmost circle is 
so large and the southernmost so small. However, the buffered area appears to 
be 150NM wide at the equator and remains that same visual width for its entire 
length.

The code for the fiddle can be found here:

http://jsfiddle.net/dtjohnst/mk9Eh/

Original issue reported on code.google.com by dtjoh...@blackswift.ca on 30 Mar 2012 at 3:16