it is not straightforward, these are the minimum settings you need:
sRoot="/system/osso/connectivity/IAP/${sKey}"
gconftool-2 --set --type string ${sRoot}/ipv4_type AUTO
gconftool-2 --set --type list --list-type int ${sRoot}/wlan_ssid "$sSSID"
gconftool-2 --set --type string ${sRoot}/type WLAN_INFRA
gconftool-2 --set --type string ${sRoot}/wlan_security NONE
gconftool-2 --set --type string ${sRoot}/proxytype NONE
gconftool-2 --set --type boolean ${sRoot}/wlan_hidden false
gconftool-2 --set --type boolean ${sRoot}/temporary true

the root name has to be unique, wlan_ssid is an integer list of characters for the SSID name, and finally if temporary is true, you are prompted whether to save the connection when the tablet tries to connect and the entry will be deleted when you disconnect.

whole script at http://pastebin.com/f486151e3 includes code to calculate the integer string value.