如何使用自定义操作安装第三方MSI？

I have a Visual FoxPro installer (exe) that I want to launch using a WiX custom action. However, I think the VFP installer is a wrapper for an MSI as I'm getting "Error 1500" which seems to denote I'm trying to run two installers at the same time.I have a Visual FoxPro installer (exe) that I w