It should definitely creep slowly on level ground, forwards or backwards, without you touching the accelerator pedal.
Yes, manual mode is much better when the driver decides and not the stupid, in this case, electronics.
If it's a Toyota dealer where you purchased I can only suggest you tell them it's not correct and they try a clutch reset. This does need their specialised equipment to carry out. As you've only just bought the car they should try the reset free of charge.
How was it on the test drive?
The clutch plate could be worn too, it can be subjected to more wear with the mmt depending on how the previous owner(s) drove it.
I do hope, for your sake, it just needs a simple reset.
I would also suggest posting your questions here
http://www.toyotaownersclub.com/forums/ which is a U.K. site.
This is more a U.S./Canadian site and as far as I know they were never inflicted with that horrible transmission.