First off I managed to convert the arms of my Broadside. Originally I had envisaged the suit holding a dual Railgun much like a soldier holds a gatling gun, however after carefully removing both the forearms from the L shaped original position I discovered that the bulk of the suits chest simply doesn't allow this in any convincing pose.
I've also had to pin the underside of the arm to join to the gun itself. Whether this works or not remains to be seen.
I finally tried a small amount of superglue remover. This was not a particularly good idea as it appeared to slightly melt the plastic. In the process of teasing the joints I managed to break the shoulder and the elbow joint. This wasn't a total disaster as with a bit of pinning and plastic rod I was able to re-pose the model to a better look. I also pinned the broken foot (which was a botched repair job that wasn't mentioned in the ebay ad... <sigh>)
I still have another 2 XV9 kits to make up but I'm holding off until the new codex arrives as I may sell them on again.