I'll try my best to answere your questions...
1. Plug and Play, is on my "Advanced" BIOS screen Haven't a clue if it's not somewhere in BIOS... on your system
2. You should have you OS Hard Drive ( C: ) set up for Primary ..and any others as Secondary (Slave)
3. UDMA "Ultra Direct Memory Access"
4. Image Mounting ...Macrium will let you "Mount" (look at) an Image When asked to do so... A screen will give you a choice to select a drive letter ...After choosing one (From Drop Down) the now "Virtual HD" will appear in windows explorer as another HD with the letter that you gave to it. You then can explore all , just as a real HD... Files\ folders, even copy them... When finished you can then "Un Mount" by right clicking on the HD and choosing "Un Mount Macrium Image"
5. Macrium 4 vs 5 .... If Version 4 doesn't see the WD Image from the recovery disk it would be worth a try to go on to Version 5 ...I have "Burned" several Recovery disks on 700 MB CD's, both Linux and WinPE's ....They fit..On 700MB CD's... you might have some bad CD's... Macrium will almost automatically create a Version 5 "Win PE" disk for you ...Just follow the prompts and let it download the 1.7 GB file from Windows ( just direct the download to place it in some new folder you create )... (WAIK...... Windows automated installer Kit)... Try to boot the Recovery CD from your set up now and see if it finds the WD drive Image... Also you can copy the Image to another drive or partition to check if Macrium will find it.
For your first try check whatever Recovery disk that you have now and boot it up ...Put the Image (copy) in several places just for a test not just on the WD. Hope this is of some help