Ron wrote:

No other saw I have could cut into the edge and any I can imagine
which could cut through the aluminum would tear up the wall in the
process.

I did a google search and thus far nothing came up. I imagine there
are some techniques or tools used for this, because people replace
old aluminum windows all the time, especially when damaged. How are
the originals removed?

How about renting a Sawzall?

You can BUY one for $17 from Harbor Freight. It would last at least for one
job...

http://www.harborfreight.com/cpi/cta...temnumber=4095