I assume you know the basics - install the HP Management Agents, ensure the SNMP community is set correctly, SNMP destination is set correctly (and it works when trying to connect from your ML server).
Any ML/DL/BL is really the same in terms of setup and configuration. The only difference here is that those agents haven't been updated in many years.. So you're probably using the 7.60 support pack. So long as you have those installed (and preferably the SMH as well), you should be good.
Just check the basics - IP connectivity, SNMP configuration, agents install. Did the machine discover OK in SIM - did SIM recognize it properly as the correct model? If not, check all the above. If it doesn't show up correctly, there's a good chance it won't accept traps.
If you want to see if SIM is getting the traps, you can check your SIM\Traps folder to see if there is an XML file there from that server. Maybe the event is coming in, but you are not seeing it in your events collections. Note that it will be a warning or informational event (i forget which) so make sure you are looking at ALL events, or looking at the events tab for the server, and that you are not ignoring info/warnings for everything.