The 824 is a modem router ...hence the sharing will only share what comes in from the ADSL line...By sticking the output from the ADSL modem into one of the 4 ports you are using the ports as a basic hub ..hence the share via wired is OK. The Wireless is connected internally to the ADSL and not to the wired switch. hence no wireless sharing.
IF either of the users have saved their logon in Outlook (or Express) the utility SIW from
http://www.gtopala.com/ will expose any ***** passwords in windoze (see the Eureka tool
). You can then use that to configure the 824 as a modem-router and bypass the modem.