Thanks for you reply. The only problem u have is that i do not have any physical access to my server. I understand that this thing may require physical access.
I have another thing in my mind. As i have written in the question, I have access to webmin and in webmin there is an option to add any logical volume to RAID partition. I can create logical volume from that interface. and after creating there is an option to add it to RAID partition. I have never tried this before. so i am not sure whether this is a good idea or not. Kindly suggest me if this is possible.