Upgrade LB after creating stack from private catalog


I have use case where I’m creating custom stack from private catalog. Everything is running ok, but after (or during?) creating that stack I just want to upgrade my load balancer based in custom LB stack under rancher/lb-service-haproxy:v0.5.9 image to point some url to one of created service on some port. I read about upgrading LB through API here How to add services in load balancer through API? but I hope there is another way to do that?

I’m not able to create configured LB in my new catalog stack because I already have one load balancer on my host listening on public port 80. In best case, is there a way to make service alias (or something) and upgrade my LB after creating new stack from my catalog? Is there a way to trigger this in process of creating that stack?

Thank you!