COMMUNITY SOLUTIONS CONTENT DISCLAIMER
1) The SQL Server service must be running under a domain-level account.
2) The SQL Server service account must have FULL CONTROL rights to the file system folder and to the share.
3) The remote share should only be accessed via UNC name. Mapped drives may not be consistently visible to the SQL Service.
Once these prerequisites are met, the UNC name can be typed into the 'Use this directory' text field on the 'Complete Backup' and/or the 'Transaction Log Backup' tabs of the Database Maintenance plan. SQL will then write backups to this location. Do not use the '…' button. This button will only enumerate local disk resources.
Note that backing up to a network share can cause significant network traffic. Make sure your network can handle this load without adversely affecting other systems or end users. You may find it beneficial to establish a dedicated physical network connection between your database server and your backup file host.