Dynamicaly Adding 'Data Store' of Mainfram

Please Help me find the solution.
I have WM6.5.We have mainframe and connect thru IMS connection pool.
we have lot of Mainframe Transaction Services which will talk to mainframe thru the IMS connect.This problem shud be a fundamental suituation in any development project.
Query 1

Host IP,port,datastore are hardcoded in the IMSConnect property tab manually.I need this to be done thru a service dynamically by accessing a property file.

Query 2

same in Mainframe Transaction SERVICEs Datastore needs to be manually typed-in in the properties tab of the service.I need this to as a dynamic and thru the properties file in the server disk.

Current Status

I have implmented of retrieving the properties file key-value pairs into the service from the local disk.NOw the problem is HOW TO SET THE RETRIEVED VALUE TO THE DATASTORE PROP OF THE IMSCONNECT or Transaction Service.
Bcas we have more than 50services by now.We dont want to change the datastore manually in all services as and when the environment changes.