That's awesome. Feel free to list a how to guide. NOTE: any how to guides are for entertainment purposes only and should not be attempted, modifying lithium batteries in any way can be dangerous, including but not limited to exploding and fire. Modifications of any kind voids all warranties and can cause tools to malfunction hurting yourself and others. That being said. How? I wanna know, I wanna know (The 10 year old inside me seems to say, whilst jumping up and down).
Also, did you have to use a plastic welder for that mod?