Disappearing Icons
I had the same problem ,and I read somewhere that they have to be on the internal memory in order to function.
They reappeared as I moved them back.
Perhaps there is already an app that solve this problem ?
Let me know if you find something.
Igo My Way for Android
I installed IGo My Way found on the internet , works fine, the problem is that it is for the android phones and it does not scale on the galaxy Tab.
I used the Igo8 on my dedicated GPS for years. Great Program.