To track the swap in CoinTracking you have to enter a trade from VEN to VET with the factor 1:100 (Buy VET - Sell VEN).
If you don't want a tax event to happen (gain or loss), it's important that you enter the asset value of the original costs of your VEN in this trade so that no profits or losses result.

You can find the cost of all your purchased VENs on the Gains page in Table 1 under "Cost". The asset values of the trade become visible when you edit the trade and click on Asset Value under Currency.
Example: If you owned 10 VEN, you will receive 1000 VET.

It is a legal grey zone, whether for a swap or a Coin/Token change the swap date or the original purchase date counts ofr long / short term gains. This might differ from country to Country. Please consult your tax account regarding this topic. 

Currently, if the asset value of the original transaction matches the swap Transaction (as described above), no tax related gain/loss event will be triggered within your CoinTracking account, however the time starts counting anew from the swap date.