CD-Rom and skirmish pack compatibility

[prancer]

I bought mow:as on cd before Christmas, and having completed all the skirmish missions am interested in buying the skirmish packs. However I don't wish to purchase the game again via steam. So my question is, is it possible to install steam, buy the skirmish packs and for them to work with my cd-rom version? I have searched for an answer but can't find one and I don' really want to install steam, buy the packs and for them to not work.

Thanks Prancer