I see that the Makita LS1030 does have a different compression spring mount than the newer "D" handle models. There is a parts schematic of your saw with the straight handle at http://www.ereplacementparts.com/makita-ls1030-miter-saw-parts-c-97_98_99_322.html.
Perhaps this will aid you in puzzling out the disassembly and repair of your compression spring. So you know, it appears that the primary compression spring for your exact model is now considered obsolete and is unavailable on most parts replacement websites.
If if your problem is just that the spring is weak, a local machine shop may be able to tell you if the spring can be re-stretched to return it to its new compression level.
Makita is known for their excellent customer service, and if you call the parts/repair division of the company (Contact info located on Makita website) the technicians may be able to not only coach you through the spring replacement process. You should also ask if the spring on a newer LS1030 series is interchangeable or if Makita themselves have any NOS springs for your saw in stock.
Good luck in your search,