Get some variables in openoffice

Hi, it's a bit difficult explain only with words..., I try:
My need is have in oo document some variables, so the bp is introduce some kind of <var_set("a",True)> and <var_get("a")> I try to explain my particular case of use:
using sale_layout module I have 5 type of order line, in my oo file I put at the begin a "table header", ex:
---------------------------------
code description q. total
---------------------------------
but when the line type is != from "article" (ex.: text, title, line, break) the table is broken, I write the text/line/break/title with "if clause", but when article line restart I need to redraw table intestation (note that there is only one loop that process all lines, that don't watch the type)
Hope is clear, i try with more "visual" example.
Thanks