Hi RBarreiros,
You cannot use P800 on ML350 G6 server, please find the ML350 G6 server quick specification which is not listed this controller and it is unsupported for G6.
Please find the ML350 G6 server quick specification.
https://h20195.www2.hpe.com/v2/Getdocument.aspx?docname=c04200238
Thanks,
Vijay