Hi Kavya,
You need to build a url like: http://xxx.com:8000/sap/bc/webdynpro/sap/BS_OVP_BP?SAP-CLIENT=100&SAP-LANGUAGE=EN&CREQUEST=000000000009&CRTYPE=CUST2P1&WDCONFIGURATIONID=BS_OVP_CU
With class cl_usmd_wf_navigation_handler you can get the parameters you need (methods get_instance and get_navigation_parameters)
The first part of the URL you can construct with cl_http_server=>if_http_server~get_location or CL_WD_UTILITIES=>CONSTRUCT_WD_URL
Cheers, Henk