ORIGINAL: cayugad
If this is the older model with a #11 nipple then a slotted breech plug, I use my CVA Staghorn breech plug removel tool. Even though I bought my Wolverine new, it never came with a breech plug removel tool.
Your right, the old CVA tool would work best. I had fogotten about it. I remember mine would work with both #11 and Musket cap nipples.
http://www.cva.com/docs/cva_catalog_2006.pdf Looks like part AC1603 for 12.95
Download the catalog, there's ordering info in the back.