You have to access the table through the XPropertySet interface. You can do this by casting the table to an XPropertSet:
// Example
XPropertySet tablePropSet = (XPropertySet)textTable;
// This is how you set a property in C#
// You have to create a new Any object to pass it as parameter
tablePropSet.setPropertyValue("HeaderRowCount", new Any(typeof(int), 1));
The "Any" object is in the "uno" namespace (not unoidl.com.sun.star.uno). You don't really need to do
typeof(int)
unless the type isn't a basic type.
new Any(1)
works fine for basic types.
BreakType example:
XPropertySet tablePropertySet = (XPropertySet)table;
tablePropertySet.setPropertyValue
("BreakType", new Any(typeof(BreakType), BreakType.PAGE_BEFORE));