Entering costs for previous quarter vAT exemption

Previous quarter (1) I had a vAT exemption; this quarter (2) I no longer do. I activated Dexxter today and want to enter all my accounts from this year, including last quarter. I have to change the date of all purchases from previous quarter to this quarter, otherwise I will not be able to enter them in Dexxter. So now I am going to enter purchases from quarter 1 in quarter 2, but I cannot claim vAT back from quarter 1 (because I had a vAT exemption at that time). In Dexxter, can I ensure that my vAT declaration for quarter 2 only includes purchases from quarter 2 and not those from quarter 1 (which I have changed the date of to quarter 2 in order to be able to enter them in Dexxter)?