Actually, I suspect it will work if you use a JDBC level 4 Informix driver (not sure if one of those is available, but it's worth a look). IPIVR is all Java (at least, it is in the Enterprise 7.0 environment I've got), so you just have to shoehorn your JDBC library into the classpath and you should be able to call Informix from it without any trouble.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.