I spoke to my accountant about this before. I can't remember the exact answer, but as far as I recall it is a simple enough process. You would value the assets and then purchase them off the sole trader (i.e. yourself) at that price.
I'm not sure exactly what happens with regards the capital allowances. I would imagine, due to the fact that the two entities are separate, that you could claim the remainder of the allowances in your final accounts as a sole trader and then start new 8 year allowances with the Ltd Co. as technically speaking they are new assets for the company, albeit being second-hand items.
For example...
Asset bought by Sole Trader in Jan 2006 for €1,000
€125 claimed by Sole Trader as capital allowance in 2006
€125 claimed by Sole Trader as capital allowance in 2007
Item sold to Ltd Co. for €750 in Jan 2008
€750 claimed by Sole Trader as remainder of capital allowances
€93.75 claimed by Ltd Co. as capital allowance in 2008
Bear in mind that as a Sole Trader you have now earned an extra €750 and will need to account for this in your final accounts.
Obviously there will be the relevant paperwork to be completed also.