I would not recommend trying to backup the actual files in use by SQL server. We had seen issues with a backup utility locking the actual data files causing unresponsiveness and resulting in the following errors being logged to the SQL error log:
Date Time spid51 Database master: IO is frozen for snapshot
Date Time spid51 Database master: IO is thawed
See the following:
In a similar vein for past employers (including my current) they tend to use something similar via SAN replication where the data files are replicated to a backup SAN at a DR facility.
Actual recovery tests revealed that, even though this was a sector by sector copy of the data files (ldf, mdf and ndf), we did at times encounter corruption due to incomplete sector writes that hadn't completed on the DR SAN.