good, that's a start... when you used connectbot, you weren't still connected to your computer were you?
here's the steps i would take:
1. put "build.prop" onto your sdcard
2. make sure your computer is disconnected from your phone and open up connectbot
3. connect to your computer through connectbot
4. type "su" (enter) and the $ should become #
5. type "mount -t rfs -o remount,rw /dev/stl5 /system" (enter) - shouldn't give you any errors - this puts your /system folder in read-write mode
6. type "cd sdcard" - this should access your sdcard (where you put the new build.prop)
7. type "cat /system/build.prop /sdcard/buildbak.prop" (backup of build.prop)
8. type "busybox cp -R build.prop /system" (copies the build.prop on your sdcard to /system over the previous version)
9. type "mount -t rfs -o remount,ro /dev/stl5 /system" to remount your system as read-only
10. follow the rest of the instructions:
Once phone is completed booting, enter "Date & time" settings and set time to 11:59pm. After time/date has changed to 12:00am (the next day), open Market and search for apps.
Open "Date & time" settings and reselect Automatic
Enjoy protected apps in the market
i actually haven't done this because i'm still on 1.5; but this should work in terms of getting build.prop onto your phone. if you've backed up build.prop already, then don't worry about step 7. let me know what step you get stuck at or the result of the step.
good luck!