If you have LMS 3.0.1 or higher, they can be found by Common Services Discovery using one of the non-CDP methods (e.g. ping sweep). However, the ASA, PIX, and FWSM devices are not supported by Campus Manager, and will never be discovered or data collected by it. Those devices are, however, supported by DFM and RME.
If you do not have LMS 3.0.1 or higher, you can manually add your ASA to DCR under Common Services > Device and Credentials > Device Management.
