/**
		* Create new system user
		* @access public
		* @param string $username System username
		* @param string $password Password
		* @param string $homedir Home directory
		* @param string $shell Shell path
		* @return SystemUser SystemUser instance 
		*/

		public function Create($username, $password, $homedir = NULL, $shell = NULL) 
		{
			
			// Check if skel exists	
			if ($this->SkelDir && !is_readable($this->SkelDir))
				Core::RaiseError(sprintf(_("User home skeleton directory (%s) not readable"), self::SKEL_DIR));
				
			// Get default shell
			if (!$shell)
				$shell = $this->ShellPath;
				
			//Get default homedir
			if (!$homedir)
				$homedir = self::HOME_DIR ."/". $username;
				
			// Check useradd tool
			if (!is_executable($this->UserAddPath))
				Core::RaiseError(sprintf(_("%s not executable"), $this->UserAddPath));
			
			//Check chpasswd tool
			if (!is_executable($this->ChpasswdPath))
				Core::RaiseError(sprintf(_("%s not executable"), $this->ChpasswdPath));
			
			if ($this->SkelDir)
				$skeldir = "-k {$this->SkelDir}";
				
			if ($this->SystemStats->IsFreeBSD)
				$args = "useradd {$username} -d {$homedir} -g {$this->UserGroup} {$skeldir} -s {$shell}";
			else 
				$args = " -d {$homedir} -s {$shell} -m {$skeldir} {$username}";
				
			$retval = $this->Shell->ExecuteRaw("{$this->UserAddPath} {$args}");
			
			if ($this->SystemStats->IsFreeBSD)
				$retval &= $this->Shell->ExecuteRaw("echo '{$password}' | {$this->ChpasswdPath} usermod {$username} $1 -h 0");
			else 
				$retval &= $this->Shell->ExecuteRaw("echo {$username}:{$password} | {$this->ChpasswdPath}");
			
			// Return SystemUser or false
			$retval = $retval ? $this->GetUserByName($username) : false;	
			
			return($retval);
		}