There is a little funny way in this mission. After several tries when I had blowed up the SCUD and then went after Guba, spetznatz or BMP's killed me so I now I started on the way to capture Guba first. So I took the Hind, flied to Gubas base, found one T-80 and an UAZ. I landed on the road, disembarked my soldiers and gave them the order to shoot the T-80 down. I myself went for the UAZ and I found it standing still there, not moving at all. So I started shooting the guys inside, first the driver, then the two spetznatz. At the same time my men shot down the T-80. Then I waited for about 30 seconds before Guba jumped out of the UAZ and a cutscene kicked in. Then I just blew up the SCUD and the rest is history. :/