PhilModJunk has an invaluable resource called Adventures in Filemaker.
The 2nd edition, 'Adventure 2 EVS' can be downloaded from his Facebook page (free with option of nerd busker donation) and I suspect from several of his forum posts.
The section within this file called 'Sorted Field Based Value Lists' demonstrates a great way to control this.
I have a copy but I'm not sure it's polite or legal to distribute it.
Link is below.
this is not a reply to your question but a remark. I would suggest that the title of your question be brief, and not a copy of the whole question, something like "Value list should not be sorted". It makes things easier in identifying the subject of the question.
This technique will solve your value list sorting problem: Extending FileMaker Pro’s value list sort capabilities using the Char() function - Soliant Consulting
It also included a demo file that shows the technique in action.