Take a look at the voucher wiki. Taxes are only removed if the voucher covers the entire base fare. Otherwise the full taxes are imposed. As another point of reference, here's what my receipt looks like from a voucher I redeemed a month ago (where the voucher didn't cover the entire fare).

PASSENGER
jmanirish

TICKET NUMBER
0012XXXXXXXXXXXXX

FARE-USD
241.86

TAXES AND CARRIER-IMPOSED FEES
37.00

TICKET TOTAL
278.86
jmanirish - Additional Fare Collection 239.65
Payment Type: Exchange, American Express XXXXXXXXXXXXXXX

You have a year to use the voucher, I would recommend just waiting and hoping you have some personal travel that you can use it on. Unless your corp expense policy is more lax and wouldn't understand the difference between ticket total and collected amount.