I was looking at this just myself over the weekend as my estate also doesn't have the long rails, basically you have 2 choices, first off you can flip up those covers and get some bars that are screwed onto the roof with an allen key, the Saab part no. for these is 32025591.
Alternately you can fit the long rails but you will need to get new trims/covers and have them painted and get hold of a set of bars (or look out for the bits on ebay) and then you'd still need to get some bars to clamp over them. If you want to do that then a single rail is part no. 32025611 and the trims are 12775636 and 12775637 (probably!).
Please double check all the part numbers though before ordering anything as I was only looking at options as I need a tow bar fitted for the bike carrier before I consider putting stuff on the roof.