How to build and run LiveXp as an HDD on a USB Pen?

Hi all, finally i decided to ask for your help as i am not able to find a solution or the way to do it.
After loooong sessions of S.R.T. (Search-Read-Try) without much success i am here to ask your help.
I am very new to PE world and i am trying the best to understand it enough to reach my goal but i am stuck.

I'll try to be short and clear.

What i need
-to have a small OS, compatible with almost all hardware, new and old, to run repair apps, anti-virus ...you know...this stuff.
-to have it running on a usb pen like if it was an hd so i can save on it the drivers i can "take" from every system i plug the usb-key in.
-Put portable apps in a folder i can reach either running the LiveXp or not (just plugging the usb-key, using the os on the hard disk) and these folder must be readable and writable so i can add-remove apps without compiling LiveXp again and again.

What i can do
Unfortunately my Xp source is not compatible with most of the projects i found here so i can only use my source with no errors with LX.061412 and the result could be nice for my needs

I can build a working LiveXp with the project of above, put it on usb and run it nicely but...

What i am not able to do
the livexp i create (with standard settings) is loaded into ram (i suppose...i am very confused at the moment) but immediately after the usb-key become unmounted and i can't see anything on it because livexp doesn't see it. Also unplugging and plugging it again has no effects.

For this reason if i put some portable app in a root folder i can't load it within livexp.
In the same way, as the os is in the ram, i can't save nothing i need onto it...then... no drivers taken from the host pc are saved on my key

So...

• Is it possible to run livexp as a normal hd, but on an usb key,  so i can add files to it, in root folders?

• If yes, which settings i have to change?

• I understood that is possible to take more and more drivers as we use livexp on other systems so that the db of them grows with the use...did i misunderstand? how to do it?

• Which format to choose to have a "flexible" system? Wim, Iso, Sdi?

• Is livexp what i need or i need something else?

I am very sorry if i asked something that, probably, is very obvious and under my nose but i can't really find the way ... too many tutorials, info, bookmarks in few hours... my brain is overloaded eheheh

Thank you in advance for having the patience to read all this post.

Ricky

EDIT: I found some answers from this thread reboot.pro/17240/ so i deleted what i think i understood