Move the desired pages into httpd-fs and regenerate httpd-fsdata.c using the PERL script makefsdata. Stage unused pages in this directory; anything here will be ignored by makefsdata. When using non-ram storage it must be invoked with the HTTPD_STRING_ATTR!
cd ~/contiki/apps/webserver (or webserver-nano, -micro, -mini, ...)
../../tools/makefsdata -A HTTPD_STRING_ATTR