User-defined symbols (.BMP and .SYM files) should be embedded in the schedule to make the schedule more portable -- when a schedule is shared, the embedded symbols go with it. Otherwise, custom symbols must be sent with the schedule as a separate files.
Symbols can be embedded in the toolbox (option 1 below, for .SYM and .BMP files), or saved as embedded symbols (option 2 below, for .SYM files only).
(1) Embed a .SYM or .BMP symbol in the schedule:
(2) Embed a .SYM symbol in the schedule:
Notes:
For the second solution, the word "EMBEDDED:" will automatically be attached to the beginning of the symbol name, and appears when it is chosen from the User Defined Shapes list in the Symbol Options dialog box.