The simplest way to change the port will be to use a 3rd party java ftp client, except it nees porting. Int20H and my self are looking into it. There is someone who has one, but doesn't want to release his work as it took ages. Its up to him whether he releases it.
Some links on the web ive found that confirm that it cant be changed it on the basic one:
http://www.guru3d.com/article/network/119/5/&e=1102
http://www.snapappliance.com/images/...es.html&e=1102
http://www.snapappliance.com/page.cf...%3D1100&e=1102