Mathias Hellquist did a detailed tutorial with captions on how he set up Bram Bos' Kosmonaut as a looper.
A video to show how I set up AUM with Kosmonaut as a looper. It is related to a post in the Facebook group iPad Musicians.
Kosmonaut has a "tape looper" built in to it, which listens to any/all incoming audio. If you bind the controls to an external midi controller you can get far longer loop segments than you can with the on-screen interface, which is limited to 8 beats, compared to 127 beats via midi.
However, as Kosmonaut does not start/stop loop segments on a given time segment it can be quite tricky to time your key/pedal presses to create a "perfect loop" like you can in AUM (which will start/stop at the next Link Quantum).
Anyways, this is me setting it up, using my guitar as the main midi input source (via MidiGuitar2) to LayR (my fave synth) and a performance preset made by the preset master Brice Beasley.