zabbix fails to compute calculated items for proxyed hosts

Zabbix server apparently expects zabbix proxy to compute calculated items
on it's behave, which the proxy is obviously unable to do.

As a test I created a template with just one item:
Type: Computed
Key: test.calc1
Expression: 1

And then added this templates to two hosts, one directly managed by
zabbix server and another managed via proxy. When I check the data for
each host the correct reading for the directly managed host and no
reading for the managed via a proxy.

So I think that zabbix server should extract all calculated items before
sending the list to the proxy and compute them by itself.