The following KB article has been released http://support.microsoft.com/kb/939364/en-us documenting support for SNMPv1 device discovery with a new hotfix
Microsoft System Center Operations Manager 2007 cannot find some network devices by using the network device discovery process. Therefore, you cannot manage these network devices in Operations Manager 2007.This problem occurs even though the network devices respond to the "GET" packets that the Snmputil.exe tool sends.
This problem occurs because Operations Manager 2007 supports only version 2 of the SNMP protocol (SNMPv2). Devices that do not support SNMPv2 ignore the "GET" packets that Operations Manager sends. Therefore, the network device discovery process cannot detect these devices. For example, this situation occurs when the devices support only version 1 of the SNMP protocol (SNMPv1) or version 3 of the SNMP protocol (SNMPv3).The Snmputil.exe tool uses both SNMPv1 and SNMPv2. These devices respond to the "GET" packets that the Snmputil.exe tool sends even if the devices support only SNMPv1.
To resolve this problem, apply the following hotfix. To do this, follow the steps in the "Hotfix installation instructions" section.After you apply this hotfix, a new Simple Network Management Protocol (SNMP) Community version list appears in the network device discovery wizard. This list contains an SNMP v1 item and an SNMP v2 item. If you select SNMP v1 from the list, the network device discovery wizard uses SNMPv1 to detect network devices.
http://go.microsoft.com/?linkid=6294451 (http://go.microsoft.com/?linkid=6294451)
Note If additional issues occur or any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. To create a separate service request, visit the following Microsoft Web site:
http://support.microsoft.com/contactus/?ws=support (http://support.microsoft.com/contactus/?ws=support)