There is currently no import functionality for I-DEAS .unv files through the API. You can import geometry from an I-DEAS .ini with the API call 'feFileReadIdeas' in section 220.127.116.11.
We will consider exposing this functionality in an upcoming release.
I saw your issue so I made my own work around to the API using FEMAP's built in programming window. I attached an API below that should allow you to import the model you need, but beware it will bring up the file select window and enter in the file name for you. Also, when entering the file name in the API be aware to use double forward slashes like "\\" so that the API can read them. Finally, I made this a sub function, so you only need to paste sub onto the botom of you program and you can use it.
I hope this helps
Thanks for your suggestions and it works really well as I want.
I am very appreciated for your help.