With Web Sphere 8.5 the default JSF version is 2.0. However, refer to Identity Manager's support matrix and see that it supports JSF 1.2 and does not support 2.0.
If left with 2.0 then errors will happen with attempt to invoke tasks from the User Interface.
To change your WAS 8.x JSF version to 1.2 you shall:
Rename "\IBM\WebSphere\AppSrv01\plugins\com.ibm.ws.jsf.myfaces.jar" to "\IBM\WebSphere\AppSrv01\plugins\com.ibm.ws.jsf.myfaces.jar.old
Then, Restart Web Sphere.