Status of things in sitemap?

I’m still struggeling with the Thing Status showing in the sitemap… I was then trying another approach using a cron job to obtain thing status on a regular basis instead of a rule on thing status change. By that I should be able to set the time interval of the cron job for each thing separately. e.g. network device more frequently, Zwave less frequently. That’s the idea.

In some input in this thread:

In order to test the basic logic, I was just trying to get the the string “Online” to show in the sitemap and used the following rule…

rule "FRITZ!Box (Modem) Status"
  when
    Time cron "0 * * ? * * *"
  then
    fritzbox_modem_status.postUpdate("Online")
end

Item:

String fritzbox_modem_status

Sitemap:

Text item=fritzbox_modem_status label="FRITZ!Box (Modem)" icon="none"

No string appears in the sitemap.

What is wrong?