The xSqlServer module has been pretty extensively updated; you should check out the latest version. That particular resource has been renamed to xSqlServerSetup, I believe, and there are lots of new resources in the module that go above and beyond what little bit was in the original:
ImplementedAs Name ModuleName Version Properties
------------- ---- ---------- ------- ----------
PowerShell xSQLDatabaseRecoveryModel xSQLServer 1.5.0.0 {DatabaseName, RecoveryModel, SqlServerInstance, DependsOn...}
PowerShell xSQLServerDatabase xSQLServer 1.5.0.0 {Database, DependsOn, Ensure, PsDscRunAsCredential...}
PowerShell xSQLServerDatabaseOwner xSQLServer 1.5.0.0 {Database, Name, DependsOn, PsDscRunAsCredential...}
PowerShell xSQLServerDatabasePermissions xSQLServer 1.5.0.0 {Database, Name, Permissions, DependsOn...}
PowerShell xSQLServerDatabaseRole xSQLServer 1.5.0.0 {Database, Name, Role, DependsOn...}
PowerShell xSQLServerFailoverClusterSetup xSQLServer 1.5.0.0 {Action, FailoverClusterNetworkName, Features, InstanceName...}
PowerShell xSQLServerFirewall xSQLServer 1.5.0.0 {Features, InstanceName, DependsOn, Ensure...}
PowerShell xSQLServerLogin xSQLServer 1.5.0.0 {Name, DependsOn, Ensure, LoginCredential...}
PowerShell xSQLServerMaxDop xSQLServer 1.5.0.0 {DynamicAlloc, DependsOn, Ensure, MaxDop...}
PowerShell xSQLServerMemory xSQLServer 1.5.0.0 {DynamicAlloc, DependsOn, Ensure, MaxMemory...}
PowerShell xSQLServerNetwork xSQLServer 1.5.0.0 {InstanceName, ProtocolName, DependsOn, IsEnabled...}
PowerShell xSQLServerPowerPlan xSQLServer 1.5.0.0 {Ensure, DependsOn, PsDscRunAsCredential}
PowerShell xSQLServerRSConfig xSQLServer 1.5.0.0 {InstanceName, RSSQLInstanceName, RSSQLServer, SQLAdminCredential...}
PowerShell xSQLServerRSSecureConnectionLevel xSQLServer 1.5.0.0 {InstanceName, SecureConnectionLevel, SQLAdminCredential, DependsOn...}
PowerShell xSQLServerSetup xSQLServer 1.5.0.0 {InstanceName, SetupCredential, AgtSvcAccount, ASBackupDir...}