As you probably know, me and Martin OK1RR are developing hamradio logging program for Linux - CQRLOG. I would have LoTW suport in CQRLOG, so I decided to do it into version 0.6.0.
First, I have visited ARRL LoTW website http://www.arrl.org/lotw/ and have read LoTW tutorial Get Started http://www.arrl.org/lotw/getStartedGuide.pdf. If you want to upload QSO to the LoTW database, you have to at first sign your adif file with certificate from ARRL. How to get this certificate is cleary described in their tutorial.
In a nutshell, you have to download and install their application called TrustedQSL and generate unsigned certificate, upload it into ARRL website or send via email. For non-US stations, you have to send scanned licence and copy of your personal card or driving licence. After that, you get signed certificate from ARRL via email (file with tq6 extension). You have to import this certificate into TrustedQSL application (you just signed unsigned certificate). It is highly recommended to export signed certificate info a file (now p12 extension) and backup it. File from email (tq6 extension) is useless and it is not for backup. If you have signet certificate, you can sign ADIF or Cabrillo files with another app callted tqsl (it is in the same package like TrustedQSL).
I would like to do it automatically in CQRLOG. So I decided to do it using tqsl in command line. As I wrote, there is also Linux version. I use Ubuntu and TrustedQSL and tqsllib is in repository and there is no problem with anything. The problem is, that not everyne use Ubuntu. On ARRL webstite are rpm packages for RedHat/Fedora but they are very old and use wxWidgets 2.4 and that is the main problem.
There is new package of tqsllib for Fedora but not TrustedQSL package. There is no chance to install it into new versions of all major distributions. There is also no chance (without changes into sourcecode) to compile it from the source code. I have contacted original author John Bloom KE3Z but without any response. I deciced to do changes myself. The true is, that my knowledge of C++ is very poor and there were a few errors during compiling with recent wxWigets libraries. Finally, I have solved all error with big help from David Hart on #wxWidgets. Thank you David!
So there are rpm packages builded in openSUSE 11.0 and Fedora but I suppose you can use this packages also in Mandriva etc. or you recompile your own package from src.rpm
Have a fun!