Sorry but I don’t really understand your issue.
If you’re using regular disposables, their names are generated the way you want, “disp<number>”. Disposables have static names only if they are named disposables. Compare definitions of disposables and named disposables in docs.
This feature is generally cool, but is problematic in your particular use case. All disposables started from the same template will have the same VPN configuration. If this is not an issue for your case, try using regular disposables instead of named disposables. It should work as is if you are not using them in ProxyVM VPN configuration.