Using CGI Escape:
http://www.myothersite.com/myotherwebapp2/foo.asp?param=1&param=3
becomes
http://www.myothersite.com/myotherwebapp2/foo.asp?param=1&param=3

Using URI Escape:
http://www.myothersite.com/myotherwebapp2/foo.asp?param=1&param=3
becomes
http%3A%2F%2Fwww.myothersite.com%2Fmyotherwebapp2%2Ffoo.asp%3Fparam%3D1%26param%3D3