[R] Changing the origin in polar.plot in plotrix package

[John Beamer]

I am trying to draw a polar plot, which is easy enough to do in the
plotrix package through the polar.plot function.

However I would like to change the origin of the length vector. For
instance all my length values are between 75 and 85, so instead of
having the origin as 0 (the default) I'd like it to be, say, 50.

Is there any way do to this in the polar.plot function, or if not is
there an additional package that will accomplish this.

I am running R 2.5 and the latest version of plotrix.

Thanks for your help
John Beamer
(http://www.hardballtimes.com)