It's seems that vCenter alarms traps are sent in SNMPv1 only. I would like to receive it as SNMPv2. Is it possible to configure the version use by vCenter (I'm using version 5.0.0) ? I can configure receiver but not the version.
I'm pretty sure v2c is the default, but technically it is pretty much identical (adds 64 bit counters) and configured at the same time/same place as v1. So configuring SNMP (non v3) in vCenter should enable both v1 and v2c jointly.
The KB articles to configure SNMP are here: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1006438 for v1/v2c.
You can test with something like Paessler's SNMP test tool and choose v2c in the tool to verify connectivity: http://www.paessler.com/tools/snmptester