structured host variable arrays within ecpg

I am porting a large C-coded application from ALLBASE SQL
(the HP-UX DBMS) to PostgreSQL. The code makes frequent use
of embedded SQL. My intention was to skip all the static stuff
and replace it by dynamic calls to libpq. So far so good, it
went pretty well and the application is running with postgres now.
But I have to face a massive lack of performance, especially on
INSERTs. I know there is lot of overhead done, if you are going
to process let say 500 insert commands. Using COPY is not really
an option. So I was trying to re-use embedded statements, but
I had to face the fact that ecpg cannot deal with structured
host variable arrays the way I expected.
Example:
EXEC SQL INSERT INTO ASimple_Values (
Primary_Key,
List_Pointer,
Parameter_Name,
Parameter_Code,
Parameter_Value,
Source_Type
)
VALUES (
:ASimple_Values[SQL_ii].primary_key,
:ASimple_Values[SQL_ii].value_list_ptr,
:ASimple_Values[SQL_ii].parameter_name,
:ASimple_Values[SQL_ii].parameter_code,
:ASimple_Values[SQL_ii].value,
:ASimple_Values[SQL_ii].source_type
);
ERROR: parse error, unexpected '[', expecting ')' or ',' at or near "["

I'm using 7.2.3 and I've found in 7.3 a slightly improved documentation
on ecpg, but I still cannot figure out if something like the above is
legal within 7.3.
Are there other alternatives to process inserts on a BULK INSERT basis
(that's the feature ALLBASE was offering)?
Thanks for your time.

Regards, Christoph