Upgrade to Spectrum 10.2 or later. The implementation of Syslog trap support for CiscoASA devices is recorded in Fixes to Certifications section in 10.2/10.2.1 online documentation.
Symptom: Syslog Events for Cisco ASA devices not working.
Resolution: Added Syslog support for Cisco ASA devices.
(10.2.0, DE158440, 00356864)
You can do the following workaround if you don't want to upgrade, i.e. destroy the CiscoASA model type models and then rediscover the devices utilizing 'create by model type' method and set Rtr_Cisco model type during the remodeling. However this will remove subviews in the Information tab that specific to CiscoASA device.