Just completing the takeoff/landing doesn't make those hours PICUS. You should really be acting as PIC for that sector for them to count as such, and technically the logbook needs to be countersigned by the de-jure commander. Nether-the-less, it seems to have become common for PICUS to be logged any time you are PF, and the UK CAA for one doesn't seem to care about countersigning. There should be an option in Logten (under the 'time' section when logging a flight' to add a P1u/s field, or you can create a custom PICUS field if you wish and log the hours that way - I think you will have to go through each flight and add them in. If doing so for ATPL upgrade you will likely only need a couple of hundred hours or so to meet the requirements, afterwhich there is no point logging them anymore that I am aware of.