Thiemo,
it looks to me like you are using inheritance just to make sure your SOURCES and TOPO_FILES tables have some common columns. If you are not actually querying the TEMPLATE_TECH table and expect to see all the rows from the other 2 tables in that one table combined, then you could use CREATE TABLE (LIKE ...) instead of inheritance. That way your "child" tables would become normal tables and you could use declarative partitioning on them.
Even if you are querying the TEMPLATE_TECH table, you could still do that by turning the TEMPLATE_TECH table into a view which performs a UNION ALL over the other tables.
