Ok, after much searching around, I found a recent, little-known, but suitable linux driver for Agere soft modems. (Suitable for IBM TP TP40 and Compaq X1000 series laptops, written by Soumyendu Sarkar, Agere Systems Inc). Spread the word if it works for you!
Follow this link:
http://www-306.ibm.com/pc/support/si...cid=MIGR-46258
Scroll down page until you find the 'linux' hyperlink under modem section. Clicking this will result in taking you to another page where you simply select an apprropriate region for downloading the driver - just follow the instructions given. This will take you to a page on the Agere website (can't seem to access directly), where you can download a beta RPM. Works perfectly!