@Raman
BODS side there is an object called Job. Which similar to Process chain in BW. I am able to load to PSA using this BODS job. The trigger for BODS job is from a web interface DS management Console. The user wants the trigger to be at the BODS.
@ Ganesh
The solution you have mentioned above is the one I am evaluating. How to trigger an Event from BODS is where I am stuck.
I read another thread and solution provided is -
Create BI source data store
Import BAPI RSPC_API_CHAIN_START
create a data flow with row generatot as input, query transform and a template as output
Click on the query transform and in the schema out Add New Function Call .
Enter process chain name in the BAPI input parameters section
Make sure that schema in and schema out has same fields by propogating the fields.
Validate and run this job ...which will execute the process chain that loads data into BI ( or you can do pretty much anything using process chain)
Will this work? Any thoughts?
This is a solution at the BODS side - I am not sure this is the right forum 
, Anyway I have posted the same in BODS forum also. Lets see.