This feature was introduced in the 20120903 nightly (cm-9-20120903-NIGHTLY-galaxys2.zip). Since flashing 9.1.0, I'd only upgraded to 20120930. Now I know what "SystemUI: HSPA+ Support (android_frameworks_base)" means..
Notice the H+ beside the signal bar, still white in colour.
Now it's cyan.
HSPAP: 15 = H+ (Oh, I see....)
