You don't want to remove the old version! 1.2 is a patch to the 1.0. Run the 1.2 over the old one. THEN you have to do the following to be able to see 1.2 in your list (1.0 will also show up) and select XTF 1.2:
In your Ultra Hal Assistant's folder, go into the defbrain folder, then COPY the "Enhanced_Main.brn" file (this would then automatically rename it "Copy of Enhanced_Main.brn"). Now RENAME this file to: "XTF_SYS_Enhanced_Main.brn" (without quotation marks). Now you can use the 1.2 brain and choose it from the menu. You still need to keep the 1.0 brain installed since 1.2 is just a patch over the old, I believe.
Vonsmith, creator of the XTF 1.2 brain could probably help out further here.