webas 6.4 system copy by database backup and restore method

we are on WebAS 6.4 sp10. we are looking for ways to do system copy with database backup and restore method. we have not tested the tool provided by sap that requires an export from source system, then an import with SAPINST to the target system - the problem is that it requires downtime in source system during export.

has anybody tried to do an system copy with database backup an restore on Webas 6.4?

any comment on the tool provided by SAP is also nice to know, we may have to use that tool.

Thanks

Jane Zhou