OpenVPN to access to service on IPSEC through ORANGE NET

Hi to all.
I’ve to connect with OpenVPN to a service via IPSEC placed on Orange but with Orange IP and not with OpenVPN IP.

Let me explain better.

I’ve this configuration.

IPFIRE have IP …251 (on every NET)
Green - 192.168.1…
Orange - 192.168.24…
OpenVpn - 192.168.3…
IPSEC on local Orange

On IPSEC I’ve to access to a service on IP 192.168.5.11

With PC in LAN GREEN (that have also access to ORANGE) is easy since I’ve add static route :
ROUTE ADD -P 192.168.5.11 MASK 255.255.255.0 192.168.24.251

But remotely I don’t found a solution.

Is possible to add this configuration to IPFIRE in order to be able to access to service via OpenVPN?
Thanks a lot
-Steve