Help with plpgsql - subst variable value

Hi all.

This my code snapshot:

CREATE FUNCTION CreateObject(varchar(600)) RETURNS int4 AS ' DECLARE  . . .   ObjectSeqName text; BEGIN . . ..
ObjectSeqName:= ''ObjectLog'' || ObjectID || ''_Seq'';    CREATE SEQUENCE ObjectSeqName start 1 increment 1 maxvalue
2147483647
minvalue 1 cache 1 CYCLE;. . .   END IF;   RETURN ObjectID;   END;
' LANGUAGE 'plpgsql';

When I run this function I got  ERROR:  parser: parse error at or near "$1"

So how can get value of ObjectSeqName in sequence/table/etc. name?