Creating the ipa went well - the first time.
the iPad complained that this ipa was not registered with the iOS, and I thought it was because I had made it registered in my own apple-ID, whereas the iPad belong to my father.
I then deleted the ipa again from the iPad, and tried again.
This time there was no new provisioning file made - and no way to delete the old from the signing software.
Also, I could not find where the preference files for either Xcode nor the app signer were stored, so I could try over from scratch.
Third time I quit the app signer and Xcode and did it over. And now it worked.
remember permitting the app-signer in your i-device as mentioned in #18 above - otherwise the app won't run!
then a zip-install as usual. Brilliant.
Now waiting to see what the power consumption will be.
Happy camper, here! Thank you, all developers!