iPhone SDK linking errors with static library

I've built my own static library with components to be reused in my project, and recently had the need to update a bunch of classes. Specifically, some methods' signatures were changed due to the fact that some classes changed names.

What happens now is that the library compiles fine on its own, but, when added to an app project, the project fails to link:

Ld build/Sucursales.build/Debug-iphoneos/Sucursales.build/Objects-normal/armv6/Sucursales normal armv6
cd /Users/nameghino/src/Sucursales
setenv IPHONEOS_DEPLOYMENT_TARGET 3.1
setenv PATH "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 -arch armv6 -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.2.sdk -L/Users/nameghino/src/Sucursales/build/Debug-iphoneos -L/Users/nameghino/src/Sucursales/../../Library/MyLibraries/MSSharedLibrary-1.0.0 -F/Users/nameghino/src/Sucursales/build/Debug-iphoneos -filelist /Users/nameghino/src/Sucursales/build/Sucursales.build/Debug-iphoneos/Sucursales.build/Objects-normal/armv6/Sucursales.LinkFileList -dead_strip -lxml2 -ObjC -all_load -miphoneos-version-min=3.1 -framework Foundation -framework UIKit -framework CoreGraphics -lsqlite3.0 -framework CoreLocation -framework MapKit -lxml2 /Users/nameghino/src/MSSharedComponents/Frameworks/MSSharedLibrary/build/Debug-iphoneos/libMSSharedLibrary.a -o /Users/nameghino/src/Sucursales/build/Sucursales.build/Debug-iphoneos/Sucursales.build/Objects-normal/armv6/Sucursales

Undefined symbols:
  "_OBJC_CLASS_$_DataCatalogService_GetSingleRow", referenced from:
      objc-class-ref-to-DataCatalogService_GetSingleRow in libMSSharedLibrary.a(MSDataCatalogSpecification.o)
  **"_OBJC_CLASS_$_DataCatalogService_ArrayOfString", referenced from:
      objc-class-ref-to-DataCatalogService_ArrayOfString in libMSSharedLibrary.a(MSDataCatalogSpecification.o)
  "_OBJC_CLASS_$_DataCatalogSe