If you convert your UCINET file to Unicode, you will be able to import it into NodeXL while retaining umlauts and other non-ASCII characters. To do so, follow these steps:
1. Open the UCINET file in Notepad.
2. Select File, Save As.
3. At the bottom of the Save As dialog box is an "Encoding" drop-down. Set it to UTF-8. (UTF-8 is a compressed version of Unicode.)
4. Save the file, optionally giving it a new file name.
5. Import the saved file into NodeXL.