Installing esxi and configuring storage is exceedingly easy. I have tried to make sense out of the questions you have posted and ... well I just think you are not understanding some fundamental things, and you are using words/terms in vague ways.
How about this: give us an actual over-view of what you are trying to accomplish?
ESXi requires very little disk space. I would start from scratch. How many physical disks do you have, and how are they configured?
So, for example, 2 x72GB disks in raid 1 array, and then 5x300GB disks in raid 5 array? (or whatever it is). The idea is that I would create a very small (say 20-50GB) logical drive that would be used to install esxi. Once that is installed, then you connect to that server using the vsphere client.
You go to configuration/storage and the installer may have auto-created a data store on the remaining free space of whatever logical drives you presented to it - you can delete that if you want, or rename it. But when you click to add storage here, it will show you whatever physical or logical disks are availble to create a datastore on. It is best to create the desired config of the physical disks using your available storage tools first. so, if you have several disks and you want them to be a larger fault-tolerant logical drive - set that up using the raid controller. Then when you "add" storage in esxi it will see that available space.
You are making this way harder than it is, and your questions are so incomplete and using vague wording that .. well you will get no effective help until you settle down and become a little more precise.
