am iincercat in comand prompt si merge super......dar cu sql-ul nu-mi dau seama de ce nu merge ca-mi formeaza stringul respectiv asa cum trebuie ....cu ghilimele cu tot ce trebuie (sau cel putin asa creed eu)....mai jos pun procedura daca vrei s-o testezi si tu.....nu trebuie decat rulata daca calea din procedura se potriveste si bineinteles database sa nu fie prea mare.....dar stiti voi mai bine ca mine ;)

 create proc _BackUp_DBName_WinRAR

 @DBName nvarchar(50),
 @param bit Out

as
set @param=0

declare
 @now    nvarchar(100),
 @luna    nvarchar(10),
 @LogicalBackup   nvarchar(300),
 @CaleBackup0   nvarchar(300),
 @CaleBackup   nvarchar(300),
 @strSQL   nvarchar(4000)

declare
 @dataRef datetime,
 @month int,
 @year int

set @dataRef=getdate()
set @month = datepart(mm,@dataRef)
set @year = datepart(yyyy,@dataRef)

select @luna=cast(month(GETDATE()) as nvarchar(50))

if len(@luna)=1 set @luna='0'+cast(@luna as nvarchar(50))

set  @strSQL='mkdir "D:\Program Files\Microsoft SQL Server\MSSQL\BACKUP\' + @DBName + '"'
EXEC master..xp_cmdshell @strSQL

-- Create a logical backup device for the full database backup
set @now=cast(day(GETDATE()) as nvarchar(50))+''+@luna+''+cast(year(GETDATE()) as nvarchar(50))+'_'+cast(DATEPART(hour, GETDATE()) as nvarchar(50))+''+cast(DATEPART(minute, GETDATE()) as nvarchar(50))+''+cast(DATEPART(second, GETDATE()) as nvarchar(50))
set @CaleBackup0='D:\Program Files\Microsoft SQL Server\MSSQL\BACKUP\' + @DBName + '\'+ @DBName + '_'+ @now
set @CaleBackup=@CaleBackup0+'.BAK'
set @LogicalBackup= @DBName + '_'+ @now

print 'EXEC master..sp_addumpdevice ''disk'', '''+@LogicalBackup+''', '''+@CaleBackup+''''
exec('EXEC master..sp_addumpdevice ''disk'', '''+@LogicalBackup+''', '''+@CaleBackup+'''')
-- Back up the full database
exec('BACKUP DATABASE ' + @DBName + ' TO ' + @LogicalBackup)

DECLARE  @LocalBackUPPath   nvarchar(255),
  @LocalBackUPDrive  nvarchar(128), 
  @TemplateFileName  nvarchar(255),
  @TemplateCharSeparator  nvarchar(128),
  @tmpSQL    varchar(8000),
  @tmpServer   varchar(8000),
  @PackerFileName   nvarchar(255),
  @PackFileName   nvarchar(255),
  @SetPasswordAutomatic  bit,
  @SetPasswordTo    nvarchar(64),
  @PackOptions   nvarchar(255),
  @FileExtention   nvarchar(32)

SET @PackerFileName = '"C:\Program Files\WinRAR\WinRAR.exe"'
SET @PackOptions = 'a -df -ep -s -d4096 -rr -m5 -ri1'
SET @LocalBackupDrive = 'D:'
SET @LocalBackUPPath = '"' + 'D:\Program Files\Microsoft SQL Server\MSSQL\BACKUP\' + @DBName
SET @PackFileName=@LogicalBackup + '.RAR"' --+ @FileExtention

SET @tmpServer='master.dbo.xp_cmdshell'
SET @tmpSQL=@PackerFileName + ' ' + @PackOptions + ' ' +  @LocalBackUPPath + '\' + @PackFileName + ' ' + @LocalBackUPPath + '\' + @LogicalBackup + + '.BAK' + '"'
EXEC master..xp_cmdshell @tmpSQL

set @param=1

return @param

GO

P.S. super hintul ;)....multumesc