Hello Sushant,
Maybe something you can do is a 2 steps process :
1. Do the host registration using the smreghost.sh
This script allows you to use the -o option to overwrite existing trusted host
Usage
smreghost -i ipAddress[:port] -u username [-p password] -hn hostname -hc hostconfigobject
-i <IPv4 address or IPv6 address enclosed in square brackets as in [IPv6 address][:port]>
-hn <Name for host to be registered>
-hc <Name of host configuration object>
[ -sh <Shared secret for the host> ]
[ -rs (enable shared secret rollover for host)
[ -u <Administrator username> ]
[ -p <Administrator password> ]
[ -f <File to store registration data in (defaults to ./SmHost.conf)> ]
[ -cf <Crypto FIPS140 mode (COMPAT or MIGRATE or ONLY)>
[ -cp <Name of crypto provider (ETPKI)> ]
[ -o <Overwrite existing Trusted Host> ]
NOTE: Any <value> that contains spaces should be surrounded by quotes.
Example: "value with spaces".
2. Use the ca-wa-config.sh -i silent and bypass the host registration step
Please note that you can use the LAX_DEBUG =true environment variable to debug any SiteMinder installation scripts on Linux/Unix
Hope it helps,
Julien.