smkeytool -importDefaultCACerts (If required to import default CA certificates)
** Import the policy store export
XPSImport customerpolicyexport.xml
** Reimport smpolicy.xml
XPSImport <siteminder>\db\smpolicy.xml -npass (This is to ensure all new authentication scheme types are imported which could have been removed while importing customer policy store xml)
Although this procedure is for MSSQL Policy Store, conceptually the steps will be the same for other Policy Stores.