If you have installed a partition for ME version, I would presume you are talking about a dual boot system.
You cannot view the contents of the ME partition from within XP after boot up , you need to select either / or with a boot manager ,prior to loading.
If you did not have second windows folder for sys files you would not be able to view the file contents in the second partition.
Therefore unless I understand your question totalling wrongly, make the ME partition a second "primary" not a "logical" partition and use Boot Magic as the boot manager (within Partition Magic) having chosen to hide /unhide the XP primary partition in P/M on boot up , you will then be given a choice of which system to load.
The "hide /"unhide" scenario accessible from Partition Magic is normally used for hiding one operating system(primary) partition while using the other.
You cannot put "ME" or any other operating system ,on a logical partition (non operating partition)
The P Magic software for example will not allow you even to try.
Also you need to load ME first ,as the op sys load up is base on the ageing principal.
You can load ME on a primary and then set up a logical for its Progam files etc.
So you could have primarys for each of XP and ME, then "x "number of logical partitions for each, up to the size of your h\drive.