Hi Panarchy, welcome to NST.
This isn't a bug we can reproduce (EasyBCD changes the Vista bootloader's timeout just fine on our machines), so we'll need some more info.
1. What version of EasyBCD?
2. What does EasyBCD show in the "Detailed Mode"
Windows Boot Manager
--------------------
identifier {9dea862c-5cdd-4e70-acc1-f32b344d4795}
device partition=E:
description Windows Boot Manager
locale en-US
inherit {7ea2e1ac-2e61-4728-aaa3-896d9d0a9f0e}
default {ced75b04-1916-11dd-9e20-dc0a2761e604}
displayorder {466f5a88-0af2-4f76-9038-095b170dc21c}
{ced75b04-1916-11dd-9e20-dc0a2761e604}
{ced75b07-1916-11dd-9e20-dc0a2761e604}
toolsdisplayorder {b2721d73-1db4-4c62-bf78-c548a880142d}
timeout 20
Windows Legacy OS Loader
------------------------
identifier {466f5a88-0af2-4f76-9038-095b170dc21c}
device partition=E:
path \ntldr
description Windows XP Professional
Windows Boot Loader
-------------------
identifier {ced75b04-1916-11dd-9e20-dc0a2761e604}
device partition=C:
path \Windows\system32\winload.exe
description Windows Vista Ultimate
osdevice partition=C:
systemroot \Windows
resumeobject {05ae1db7-1880-11dd-b3b9-806e6f6e6963}
Real-mode Boot Sector
---------------------
identifier {ced75b07-1916-11dd-9e20-dc0a2761e604}
device partition=E:
path \NST\nst_mac.mbr
description Mac OS X Leopard