It would not be possible. Unless a patch by blizzard allowed it, which i doubt happening since most people play TFT - and the campaigns are typically in W3X not W3M format, making them unusable for use in ROC, To use a campaign in ROC you'd have to find a ROC suitable version. Which exists mainly for ones such as Darky27's The spider queen campaign, made prior to the Retail Version of TFT.
Plain and simple, You need to get TFT. | 
