Retrieve value within a data flow

hi,

I am doing a data flow to insert data into a dimension table(A) and master surrogate key table(B). Master surrogate key table(B) will be inserted prior to dimension table(A). My dimension table(A)'s key is depend on the last key in master surrogate key table(B). The data flow started from a flat file and checking if the key found in dimension table. If not found, insert a record into B. Then generate the new record to A with max id from B.

My question is how to retrieve the max id in master surrogate key table(B) in a data flow and use it as an input to my dimension table?

Have you tried the LOOKUP component? That's the sort of thing it is designed to do.

-Jamie