Ok...so it seems you have a couple of options here.
1. If you have an attribute in the footprints data that has the texture names...you can create (in the CGA code) one variable that references the folder that has the texture images (i am assuming jpg) and another variable that represents the texture name..then you can connect that CGA texture name attribute to the footprint texture name attribute.
Then connect the attributes here...
2. If you want to use the "building names" from your footprint attributes....you will possibly need to rename your texture images to match the building names
for example...it your building name is "building1"----rename the texture image for that building "building1.jpg". Then use the following code..
Then follow the "connect the attributes" section above to connect your building name attribute to your CGA attribute (I called it "BuildingTexture_From_Attribute_Table") and then the rule should put the appropriate texture to the building.
I hope this helps. Let me know how it goes.