[CentOS] question about mounting external USB HD

Hello,

I have a server running CentOS 4.7 and I want to add a new USB-HD for 
backup some data. I made the file system as ext3 with the command:
/
mkfs -t ext3 /dev/sdb1/

After that I did add a new Volume Group and Logical Volume 
(/VolGrup01-LogVol01) /on that file system and mounted it as /backup. It 
worked fine but when I did reboot the server It wont mount /backup and I 
got the following error even after the system boots and I try to mount 
it manually:

/mount: special device /dev/VolGrup01/LogVol01 does not exist/

I will appreciate any comment or suggestion about the best way to get 
through this.

Regards,

--Ivan.