How to go about using a custom calling convention

[FrankvdStam]

I'm dealing with a variation of thiscall where the this pointer is passed via EAX instead of ECX. Apparently this is some msvc-only optimization. While the detour is working with "thiscall" from #8, it is preserving ECX while I need EAX.

https://reverseengineering.stackexchange.com/questions/16919/what-compiler-uses-a-calling-convention-that-uses-eax-as-the-first-argument-the

Is there any way that I can tell the lib to use EAX or to control what registers go where? Would like to avoid writing my own asm to fix this.

Awesome library, thanks so much for the hard work!