Complex/elaborate user-defined base types

Hi,
I am trying to create complex user-defined base types and have some 
difficulties.

I started with the examples (complex, point, path) and I had no problem 
at all
creating similar user-defined types, with fixed or variable length. They
perform very good in all my tests  (inserts, selects and so on).

The problem I have is  I need more elaborate types, types  containing other
previously defined types.
I try for example to create and use something like:

typedef struct SymbolType
{   int32         size;   bool             antialias;   char             character;   bool             filled;   text
        *font;   int32            gap;   text            *image;   text            *name;   PathType        *points;
SymbolStyleType*style;   int32            transparent;   int32            type;
 
} SymbolType;

where PathType and SymbolStyleType are also user-defined type with variable
length (PathType is a variable-length type containing a list of 
PointType elements
(x, y) and SymbolStyleType has a variable-length array of integers).

I tried several scenarios inside the IN/OUT functions and none of them
works 100%. It is either the data overlaps depending on the sizes of the 
variable-length
elements, or I have various memory problems (especially when doing SELECT on
a column containing this type).
I tried to use an additional "void *data" member at the end, where to 
dump all the
variable contents and retrieve them when needed, but I could not make it 
work at all.

Anybody tried to do do something similar and want to share some thoughts on
this one?

Best regards,
Jean