Certificate Install without mandatory PIN lockscreen Google Support says:


  The type of lock that's acceptable may be predetermined by your system
  administrator.


Where I can define what's acceptable? I can regenerate the certificate if needed.

So I can use slide lockscreen again.

(I'm using CM9 RC1, Android 4.0.4)
I've described how to do exacly this on my page, "Installing CAcert certificates on Android as 'system' credentials without lockscreen - instructions" at http://wiki.pcprobleemloos.nl/android/cacert

I've also posted it on the cyanogenmod forum:
http://forum.cyanogenmod.com/topic/82875-installing-cacert-certificates-on-android-as-system-credentials-without-lockscreen/

Basically, the commands are:

openssl x509 -inform PEM -subject_hash_old -in root.crt | head -1


To get the correct filename, then convert the certificate:

cat root.crt &gt; 5ed36f99.0
openssl x509 -inform PEM -text -in root.crt -out /dev/null &gt;&gt; 5ed36f99.0


Copy them to /system/etc/security/cacerts/ and chmod the new .0 files to '644'.
Reboot and verify. On your android device select 'Clear cerficates' and you are able to remove the pin (by entering the pin and changing your lockscreen to 'none' or 'wipe'

Here I used the CAcert root certificate, but you probably want the class3.crt certificate as well, or use your own certificates.