Include transaction costs in 'buy' trade / linking cost base increase

At present, there's no option within the 'buy trade' to include transaction costs incurred in relation to the buy trade (noting, there's only a field for brokerage costs). Would it be possible to include a new field to cover this? I raise this as when acquiring shares in France, there is a transaction tax amount that's applied based on the relative buy trade value - this may also be helpful for other users that manually convert funds into a separate foreign currency and incur commission fees there. I note there is the ability to include a cost base increase, but there's also no functionality to link this to a specific buy trade [in the same manner as being able to link sell trades to the original buy trade] - again, can this functionality be included/updated?