unable to assign value to composite column in trigger

The following is a snippet from a trigger i am using:

_mycompositeType.user_id = (OLD).mycompositeType.user_id;
...do some stuff... --notice that assigning from the trigger record
works

but later on...

(new).mycompositeType.transaction_id := _transaction_id;

Fails with syntax error at or near "("

I have tried removing the () and it fails with "syntax error at or
near "new""

non composite column can be assigned to in the trigger just fine:

new.other_columm := 5; --gives no issues

How can a composite column be assigned to inside a trigger?

Thanks

Ketema J. Harris
www.ketema.net
ketema(at)ketema(dot)net
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