Increasing combat values by techs..

[vonCarstein1984]

I want that certain techs to increase the combat values of my units
(f. e. researching better a better Machinegun should give increased soft attack values to all the units in the infantry tree)
is that doable?

because I remember mod_34 where there was kind of a workaround implemented with a std country annexing anonther std country (offmap countries) and when that happend the values of all units got upgraded...
is such a workaround still necessary?

edit: nevermind it's working fine i just had a typo.. -.- sorry

edit2: No I got it wrong. It's not working fine.
Thats the command I'm using:

command = { type = soft_attack which = infantry value = 1 when = now }

All the units I already built got the upgrade but all units that I build afterwards dont get the bonus. Has anyone an idea on how i could do that?
It seems I now finally found the reason for the workaround (std annexed std thingy) in Mod34

edit3: ok.. in case any one is interested I'll post it here:
this is peculiar
when I change when = now to when = on_upgrade something strange happens...
the game now somehow remembers which upgrades a unit is supposed to get (I'm not sure how its doing that but ok)
but it only executes the change when something happens... f. e. anyone annexes anybody...

does anyone know what kind of "event" triggers on_upgrade?
because having 2 countries that own dummy provinces and that keep annexing each other seems to be a rather inelegant solution
or maybe anyone knows a different "when =" option I could use for the same effect?