Yes, I mean I already promised to release the sources before... uhm. well..
About the include files, i was refering to the uIP include files. Make sure cc65 finds them by specifying the -I{include_path} parameter.
For linking, make sure ld65 finds the cc65 library path by specifying -L{lib_path}. If you wish to build with the standard cc65 C64 framework you need to put {lib_path}\c64.o as the first input file, then all your contiki *.o files and finally c64.lib to make it work. This took me quite some time to figure out
Also, you might wanna edit uipopt.h to suit your needs.
Hope this helps!