Vista - Linker error when linking unmanaged library with manged exe

Hi,

I have an unmanaged static library which im linking into a managed
exe. The unmanaged library is being build by VS 2005 with old syntax
check enabled and no clr option. The managed exe is also build by VS
2005 with old syntax enabled and clr option enabled.

Now, i have added one function in one of the classes of the library,
and i try to call it from the managed exe, and the linker is giving me
the following error:-

error LNK2028: unresolved token (0A000168) "public: bool __thiscall
CStorageEx::isFunc(void)" (?isFunc@xxxxxx@@$$FQAE_NXZ) referenced
in function "public: virtual class System::String ^ __clrcall
Project::ManagedClass::get_Func(void)" (?
get_Func@xxxxxx@Project@@$$FU$AAMP$AAVString@xxxxxx@@XZ)
error LNK2019: unresolved external symbol "public: bool __thiscall
CStorageEx::isFunc(void)" (?isFunc@xxxxxx@@$$FQAE_NXZ) referenced
in function "public: virtual class System::String ^ __clrcall
Project::ManagedClass::get_Func(void)" (?
get_Func@xxxxxx@Project@@$$FU$AAMP$AAVString@xxxxxx@@XZ)

The error is removed if i FIRST call the newly added function in the
unmanaged library, and then use it in the managed exe.

Now im unable to understand the reason......
Y is it happening? .......
Please any solutions.......??

Thanks,
Saad