Field Dependency Business Mapping - set value from field

[radu]

I'm trying to setup a business map that would copy the value from quantity in description when a user pushes edit on a Contact.
I can assign constants with the <change> action but I can't assign values from a field on a same form. I tried this:
<map>
<originmodule> <originname>Contacts</originname> </originmodule>
<dependencies>
<dependency>
<field>firstname</field>
<actions>
<function>
<field>description</field>
<name>fieldDep_GetField</name>
<parameter>firstname</parameter>
</parameters>
</function>
</actions>
</dependency>
</dependencies>
</map>

... and play a bit around but I can't seem to get any value from the firstname field into description(or anywhere else). I tried to follow the wiki example for this but I could not get any result. I think I'm not doing it correctly but cannot find any other example to follow. So if anybody already done that please enlighten me

Thanks.