Ok, i think i know why you are confused... With kennels that use Hroark's solution ( meaning they mount sd ext as /data, or move all of user data to the ext) the phone reads the ext as /data. Meaning menu> settings> storage will accurately display available memory.
The new kk (2.0) only moves /data/app (or only user apps, not settings, dalvik, text messages, or anything else considered 'user data') to the ext. the rest is left on the real /data
The storage menu inaccurately displays available memory as a result of this.
The kernel also has the SECRET ability to mount the swap partition as dalvik cache (if formatted to ext 4)
Kouma hasn't clearly explained how to do this in one place as it's 'super secret' there are clues in his posts on how to do this...
If you open terminal emulator and type
It will display all of the partitions (named by their mount points) and information on their size and available space
Note it gives the mount point (dev/block/*) followed by its purpose
For example dev/block/mmvblk0p2 is sd-ext (also in my case /data because i use a kernel that mounts the entire /data partition to sd-ext)
This accurately displays the available memory
so, in short, just because you can't see it, it doesn't mean it's not there and being used
(unless u view df and still don't see it, then it's really not there. Lol)
And if you still confused, please ask specific questions.
or if i miss understood you question all together, please try to rephrase it differently, or direct me to the correct post.