Rewrite Source Address (Masquerading)

Hi, guys.

I wanted to understand how we managed to do a Rewrite Source Address (Masquerading).

My situation:

I want my ssl vpn network to reach another network behind an IPSec VPN. To avoid having to publish a new route, I would like to rewrite the output to my firewall interface.

My Firewall: 192.168.10.1
My local network: 192.168.10.0/24
My VPN network: 172.16.254.0/24
Network at the other end: 192.168.254.0/24

I've tried using this setting:

SourceNAT would be IP 192.168.10.1. Unfortunately it didn't work.

Thanks for the help in advance.