How to use SEH registers

[0xF6]

I'm trying to use Protected Mode Exceptions registers
As sample code:

mov rax, seh_handler
mov fs:[0], rax

I'il trying write

var @catch = asm.CreateLabel("seh_handler");
...
asm.mov(rax, __[@catch]);
asm.mov(fs, rax);
...

This does not seem to be the correct use, for example, I cannot specify the index where to write the address of the SEH handler procedure
the question is, how to use these registers correctly?

[wtfsck]

There's an example in the README:

https://github.com/icedland/iced/blob/master/src/rust/iced-x86/README.md#assemble-instructions

let _ = ptr(rax).fs(); // fs:[rax]