Hi,
What is the hardware information you need from the devices?
Please share the equivalent CLI commands that you use to get the information you want using SNMP.
For environmental variables like fans, power supplies and temperature the following tables may help:
ciscoEnvMonTemperatureStatusTable (1.3.6.1.4.1.9.9.13.1.3)
ciscoEnvMonVoltageStatusTable(1.3.6.1.4.1.9.9.13.1.2)
ciscoEnvMonFanStatusTable(1.3.6.1.4.1.9.9.13.1.4)
ciscoEnvMonSupplyStatusTable(1.3.6.1.4.1.9.9.13.1.5)
All these tables are part of CISCO-ENVMON-MIB, you can check if your IOS supports it in the following link:
http://tools.cisco.com/ITDIT/MIBS/MainServlet
I hope this helps.
Andres